got a problem in ltoa ()

hello, i have a problem in converting an octal number to its binary form, using ltoa...
well i have a small program in C , that does this job , just fine ,
but i have to make it in C++, meaning i will not need any scanf() , so here is the problem , i dont know how i can feed the ltoa ! if i convert a decimal number to octal (suppose i is the decimal number , i convert it to octal and save it again in 'i' , when i use it in ltoa, it wont work!!)
(see the following example, it just works fine, but if i omit scanf("%o",&i) , and i feed the ltoa (the number 77 which is octal )it wont work! if i use a decimal number and convert it to octal and then feed the ltoa , again it wont work!! where is the problem ? is there any counterpart for C++? or a way to manipulate octals ? i mean we have "%0" in C , do we have such thing is C++ that returns an octal number?

Code:

---

/* ltoa example */
#include <cstdio>
#include <cstdlib>

int main ()
{
  int i,k;
  char buffer [sizeof(long)*8+1];
  char * str;
  printf ("Enter a number: ");
  scanf ("%o",&i);
  ltoa (i,buffer,10);
  printf ("decimal: %s\n",buffer);
  ltoa (i,buffer,16);
  printf ("hexadecimal: %s\n",buffer);
  ltoa (i,buffer,2);
  printf ("binary: %s\n",buffer);
  system("pause");
  return 0;
}

---

The global main function returns an int, and ltoa is non-standard. Unfortunately, there is no direct standard library replacement for ltoa, except for the special cases of octal, decimal and hexadecimal. As a basic example:

Code:

---

#include <iostream>

int main()
{
    int num;
    std::cout << "Enter a number in octal: ";
    std::cin >> std::oct >> num;

    std::cout << "decimal: " << std::dec << num << std::endl;
    std::cout << "hexadecimal: " << std::hex << num << std::endl;
}

---

You could use a stringstream to actually save the converted result to a string instead of printing it immediately.

Quote:

---

Originally Posted by laserlight

The global main function returns an int, and ltoa is non-standard. Unfortunately, there is no direct standard library replacement for ltoa, except for the special cases of octal, decimal and hexadecimal. As a basic example:

Code:

---

#include <iostream>

int main()
{
    int num;
    std::cout << "Enter a number in octal: ";
    std::cin >> std::oct >> num;

    std::cout << "decimal: " << std::dec << num << std::endl;
    std::cout << "hexadecimal: " << std::hex << num << std::endl;
}

---

You could use a stringstream to actually save the converted result to a string instead of printing it immediately.

---

would you explain more ? i have no clue what a string stream is !( havent read about that yet!

Quote:

---

Originally Posted by Masterx

would you explain more ? i have no clue what a string stream is !( havent read about that yet!

---

Read about that part then :)
You could search the Web if necessary.

tanx ok.im on it

i couldnt manage to figure stringstream stuff out ! so i made my own Octal to Binary convertor
please check this out and tell me if anything is wrong. many tanx in advance :

Code:

---

int Oct2Bin(int n)
{
        int a[6],i=0,t=0;
        string str,b;
        while(n!=0)
        {
                a[i]=n%10;
                n=n/10;
                if(a[i]>7)
                t=1;
                i++;
        }
        i--;
        if(t==0)
          for(;i>=0;i--)
          {
                  switch(a[i])
                  {
                          case 0:
                          if (!str.empty())
                          str.append("000");
                          else
                          str="000";
                          break;

                          case 1:
                          if (!str.empty())
                          str.append("001");
                          else
                          str="001";
                          break;

                          case 2:
                          if (!str.empty())
                          str.append("010");
                          else
                          str="010";
                          break;

                          case 3:
                          if (!str.empty())
                          str.append("011");
                          else
                          str="011";
                          break;

                          case 4:
                          if (!str.empty())
                          str.append("100");
                          else
                          str="100";
                          break;

                          case 5:
                          if (!str.empty())
                          str.append("101");
                          else
                          str="101";
                          break;

                          case 6:
                          if (!str.empty())
                          str.append("110");
                          else
                          str="110";
                          break;

                          case 7:
                          if (!str.empty())
                          str.append("111");
                          else
                          str="111";
                          break;
                  }
          }
        cout<<str;

        if(t==1)
          {
               
                return -1;
return 0;          }
}

---

What, exactly, about stringstreams did you fail to understand?

Quote:

---

Originally Posted by Elysia

What, exactly, about stringstreams did you fail to understand?

---

tanx for your attention dear Elysia, well cause i was kinda in hurry i just googled the string stream and a bunch of links appeared! glancing at the examples , i couldnt find it out! anyway ,(i will go for it next time , ) would you now tell me why this program fails! (im sure thats because of loop where Memory[5][i] gets stuffed! )

Code:

---

#include <cstdlib>
#include <iostream>
#include <cstdio>
#include <string>
using namespace std;

string ob(int);


int main(int argc, char *argv[])
{
    int b,i=0;
    char memory[5][10];
    string str;
    cout<<"enter a number ";
    cin>>b;
    str = ob(b);
    if (str =="no")
    {
            cout<<"your number is not octal!!";
    }
    else
    {
        for (int i=0;i<9;i++)
        {
              memory[5][i]=str[i];
       
        }
       
    }
    //cout<<memory[5][i];
  // cout<<ob();
    system("PAUSE");
    return EXIT_SUCCESS;
}
string ob(int n)
{
        int a[6],i=0,t=0,it;
        string str,b,str1,str2,not_octal;
       
       
        while(n!=0)
        {
          a[i]=n%10;
          n=n/10;
          if(a[i]>7)
          t=1;
          i++;
        }
        i--;
        if(t==0)
          for(;i>=0;i--)
          {
          switch(a[i])
          {
            case 0:
            if (!str.empty())
              str.append("000");                 
            else str="000";
            break;
           
            case 1:
            if (!str.empty())
            str.append("001");
            else str="001";
            break;
           
            case 2:
            if (!str.empty())
            str.append("010");else
            str="010";
            break;
           
            case 3:
            if (!str.empty())
            str.append("011");else
            str="011";
            break;
           
            case 4:
            if (!str.empty())
          str.append("100");else
            str="100";
            break;
           
            case 5:
            if (!str.empty())
            str.append("101");else
            str="101";
            break;
           
            case 6:
            if (!str.empty())
            str.append("110");else
            str="110";
            break;
           
            case 7:
            if (!str.empty())
            str.append("111");else
            str="111";
            break;
          }
          }
          str1="000000";
          str2="000";
              if (str.length()==3)
              {
                                  str1.append(str);
                                  str=str1;
              }
                                 
              if (str.length()==6)
              {
                                  str2.append(str);
                                  str=str2;   
              }           
             
              cout<<str;
       
        if(t==1)
          {
                not_octal="no";
                //printf("Not an Octal number\n");
                return not_octal;
return str;          }
}

---

Code:

---

    int num;
    std::cout << "Enter a number in octal: ";
    std::cin >> std::oct >> num;

    std::stringstream stream;
    stream << num;
    std::cout << stream.str().c_str();

---

Example: http://www.cppreference.com/wiki/io/...m/constructors

As for your code, element 5 does not exist. 0-4 does.
Furthermore, you MUST improve your indentation.
And avoid working with legacy char.
If you work with arrays, use std::tr1::array or boost::array.

Quote:

---

Originally Posted by Masterx

Code:

---

{
        int a[6],i=0,t=0;
        string str,b;
        while(n!=0)
        {
                a[i]=n%10;
                n=n/10;
                if(a[i]>7)
                t=1;
                i++;
        }
        i--;
        if(t==0)
          for(;i>=0;i--)
          {
                  switch(a[i])
                  {
                          case 0:
                          if (!str.empty())
                          str.append("000");
                          else
                          str="000";
                          break;

                          case 1:
                          if (!str.empty())
                          str.append("001");
                          else
                          str="001";
                          break;

                          case 2:
                          if (!str.empty())
                          str.append("010");
                          else
                          str="010";
                          break;

                          case 3:
                          if (!str.empty())
                          str.append("011");
                          else
                          str="011";
                          break;

                          case 4:
                          if (!str.empty())
                          str.append("100");
                          else
                          str="100";
                          break;

                          case 5:
                          if (!str.empty())
                          str.append("101");
                          else
                          str="101";
                          break;

                          case 6:
                          if (!str.empty())
                          str.append("110");
                          else
                          str="110";
                          break;

                          case 7:
                          if (!str.empty())
                          str.append("111");
                          else
                          str="111";
                          break;
                  }
          }
        cout<<str;

        if(t==1)
          {
               
                return -1;
return 0;          }
}

---

---

Quote:

---

Originally Posted by Elysia

Code:

---

    int num;
    std::cout << "Enter a number in octal: ";
    std::cin >> std::oct >> num;

    std::stringstream stream;
    stream << num;
    std::cout << stream.str().c_str();

---

Example: http://www.cppreference.com/wiki/io/...m/constructors

As for your code, element 5 does not exist. 0-4 does.
Furthermore, you MUST improve your indentation.
And avoid working with legacy char.
If you work with arrays, use std::tr1::array or boost::array.

---

mant tanx dear Elysia . my bad ( i completely forgot that!!tanx again )
about indentation , is the above post indented properly?
and about boost arrays ! is it not necessary to install boost library before using them? or are they just ordinary header files?! (include them and use em!)

Refer to http://cpwiki.sourceforge.net/Indentation for indentation advice and how it's done properly.
Boost::array exists in a header, so you only need the header and no compiling & installing. Unless your compiler supports TR1, in which case you should be able to find it in std::tr1::array in a header called "array" I believe (or some such).

by the way , that didnt help either! you know the program compiles fine , it ouputs the binary form , there a " Windows dont send error window " appears !! and it crashes!!

Code:

---

#include <cstdlib>
#include <iostream>
#include <cstdio>
#include <string>
using namespace std;

string Oct2Bin(int);


int main(int argc, char *argv[])
{
        int b,i=0;
        char memory[5][10];
        string str;
   
        cout<<"enter a number ";
        cin>>b;
   
        str = Oct2Bin(b);
        if (str =="no")
        {
                cout<<"your number is not octal!!";
        }
        else
        {
            for (int i=0;i<9;i++)
            {
                  memory[4][i]=str[i];
       
            }
       
        }
    //cout<<memory[5][i];
  // cout<<ob();
        system("PAUSE");
        return EXIT_SUCCESS;
//in the name of God
//Octal To Binary Convertor
//Protype : string Oct2Bin( int );
}

string Oct2Bin(int n)
{
        int a[6],i=0,t=0;
        string str,str1,str2,not_octal;
        while(n!=0)
        {
                a[i]=n%10;
                n=n/10;
                if(a[i]>7)
                t=1;
                i++;
        }
        i--;
        if(t==0)
          for(;i>=0;i--)
          {
                  switch(a[i])
                  {
                          case 0:
                          if (!str.empty())
                          str.append("000");
                          else
                          str="000";
                          break;

                          case 1:
                          if (!str.empty())
                          str.append("001");
                          else
                          str="001";
                          break;

                          case 2:
                          if (!str.empty())
                          str.append("010");
                          else
                          str="010";
                          break;

                          case 3:
                          if (!str.empty())
                          str.append("011");
                          else
                          str="011";
                          break;

                          case 4:
                          if (!str.empty())
                          str.append("100");
                          else
                          str="100";
                          break;

                          case 5:
                          if (!str.empty())
                          str.append("101");
                          else
                          str="101";
                          break;

                          case 6:
                          if (!str.empty())
                          str.append("110");
                          else
                          str="110";
                          break;

                          case 7:
                          if (!str.empty())
                          str.append("111");
                          else
                          str="111";
                          break;
                  }
          }
          str1="000000";
          str2="000";
              if (str.length()==3)
              {
                        str1.append(str);
                        str=str1;
              }

              if (str.length()==6)
              {
                        str2.append(str);
                        str=str2;
              }

        cout<<str;

        if(t==1)
          {
                  not_octal="no";
                //cout<<"Not a Octal number\n";
                return not_octal;
return str;          }
}

---

Code:

---

#include <iostream>
#include <string>
#include <sstream>

int main()
{
        int Num;
        std::cout << "Enter a number: ";
        std::cin >> std::oct >> Num;
       
        std::stringstream sstr;
        sstr << Num;
        std::cout << sstr.str().c_str() << std::endl;
}

---

Although, don't ask me why the output is incorrect; I'm not much into this kind of thing.

well, so how should i know what is wrong with it! im really confused!

Why not have Oct2Bin take a string as its argument? If you really want it to take an int as an argument then you are merely expressing the number in binary as opposed to converting it from an octal representation to a binary representation.

this is a better base conversion algorithm:

Code:

---

std::valarray<unsigned int> baseConvert(unsigned int value,unsigned int base)
{
    unsigned int digits = 1+log((double)value)/log((double)base);
    std::valarray<unsigned int>result(digits);
    for(int i=0;i<digits-1;i++)
    {
        result[i]=value%base;
        value/=base;
    }
    result[digits-1]=value;
    return result;
}

---

check out the method of complements

Quote:

---

Originally Posted by laserlight

Why not have Oct2Bin take a string as its argument? If you really want it to take an int as an argument then you are merely expressing the number in binary as opposed to converting it from an octal representation to a binary representation.

---

the reason i take an integer argument is that , this is an emulation project , this simple computer uses octal system to manipulate stuffs, and any program written in the language of this system must use octal! so i assume the user inputs his data, now its the time to convert the stuff to the machine language and store it in memory! thats why im trying to convert an integer octal number to its binary string , so that i can dump this low-level instruction in memory!

Quote:

---

Originally Posted by m37h0d

this is a better base conversion algorithm:

Code:

---

std::valarray<unsigned int> baseConvert(unsigned int value,unsigned int base)
{
    unsigned int digits = 1+log((double)value)/log((double)base);
    std::valarray<unsigned int>result(digits);
    for(int i=0;i<digits-1;i++)
    {
        result[i]=value%base;
        value/=base;
    }
    result[digits-1]=value;
    return result;
}

---

check out the method of complements

---

many thanx pal . i appreciate it.

i really need to know why my program crashes! please some one help me ! this part plays a crucial role in my project! if i fail to solve this , my project fails to dump instruction in machine language (binary format) into the memory (a 2D array)!!:(

well, first thing's first:

quit doing it the hard way and see if your problem goes away. if not, then debugging will be easier!

also, i don't see why you're forcing the user to input something in valid octal representation - just convert dec->oct. any number is a valid octal number, it just may be represented in a different format (in our case, decimal)

Quote:

---

Originally Posted by m37h0d

this is a better base conversion algorithm

---

No, it is a more general base conversion algorithm, but "worse" in this case since it does not take advantage of the one to one mapping between octal digits and three consecutive binary digits.

Quote:

---

Originally Posted by Masterx

the reason i take an integer argument is that , this is an emulation project , this simple computer uses octal system to manipulate stuffs, and any program written in the language of this system must use octal!

---

That does not seem like a convincing reason to use an int argument. Once you have stored it as an int value, the original representation of the input no longer matters.

Quote:

---

Originally Posted by Masterx

so i assume the user inputs his data, now its the time to convert the stuff to the machine language and store it in memory! thats why im trying to convert an integer octal number to its binary string , so that i can dump this low-level instruction in memory!

---

Why waste time reading the input as an int and then converting the int to a binary string? You might as well read the input as a numeric string in octal representation and then do the conversion to binary representation directly.

Quote:

---

Originally Posted by Masterx

i really need to know why my program crashes!

---

Use a debugger to step through the program. This can help you pinpoint the crash.

arguably so i suppose but i'm not totally convinced that's a substantive advantage

Quote:

---

Originally Posted by m37h0d

well, first thing's first:

quit doing it the hard way and see if your problem goes away. if not, then debugging will be easier!

also, i don't see why you're forcing the user to input something in valid octal representation - just convert dec->oct. any number is a valid octal number, it just may be represented in a different format (in our case, decimal)

---

this feature is going to be implemented ! (some part of the program now supports decimal input too, )

Quote:

---

Originally Posted by laserlight

No, it is a more general base conversion algorithm, but "worse" in this case since it does not take advantage of the one to one mapping between octal digits and three consecutive binary digits.


That does not seem like a convincing reason to use an int argument. Once you have stored it as an int value, the original representation of the input no longer matters.


Why waste time reading the input as an int and then converting the int to a binary string? You might as well read the input as a numeric string in octal representation and then do the conversion to binary representation directly.


Use a debugger to step through the program. This can help you pinpoint the crash.

---

its done.i'll do it this way. so far so good.
before i head for debugging stuff(which i dont know how the stuffs work !) is it right to say that the program is ok ?. i mean i didnt do anything contrary to the basics of C++!?

Quote:

---

Originally Posted by Masterx

is it right to say that the program is ok ?. i mean i didnt do anything contrary to the basics of C++!?

---

Well, what is the current code for which you want such an evaluation to be made?

ive finaly figured it out! the crash is because of string str;
in the loop

Code:

---

            for (int i=0;i<9;i++)
            {
                  memory[4][i]=str[i];
       
            }

---

i tried to access the str by using index ! and it showed me that string str is rather different than string str[length] !! so that was the catch!
after that i noticed that the function doesnt return anything ! at least if in returns anything , that thing is empty!! why ? because i tried to copy str elements to a buffer using

Code:

---

char buffer[12];
int length=0;

length=str.copy(buffer,9,0);
buffer[length]='\0';

---

and then tried to print the stuffs (buffers) on the console screen! but nothing was printed!
well where is the catch this time ? is there any other ways to copy this (string str) form of string to another string (like string str1[n])?

Quote:

---

Originally Posted by laserlight

Well, what is the current code for which you want such an evaluation to be made?

---

the codes we were discussing !here:
for (int i=0;i<9;i++)
{
memory[4][i]=str[i];

}
(it seems i was wrong , idid it the wrong way .)

Quote:

---

Originally Posted by Elysia

If you work with arrays, use std::tr1::array or boost::array.

---

Can you explain why? What's wrong with the built in arrays?

They are unsafe (at least boost::array will assert if you access out-of-bounds), does not provide you any means to get its length, and does not always work with well standard containers.

Quote:

---

Originally Posted by manzoor

What's wrong with the built in arrays?

---

Read Stroustrup's answer to the FAQ: What's wrong with arrays?

what about me then ? any help?! how to copy str struffs to a char * based string?!!

Quote:

---

Originally Posted by Masterx

what about me then ? any help?! how to copy str struffs to a char * based string?!!

---

Why do you want to use C style null terminated strings in the first place? I am afraid that I find your posts #23 and #24 to be rather incoherent due to the lack of context.

well, in post 23 and 24 im saying that because i declared str as "string str" i couldnt use subscripting to point to each elements of str and then copying them to another string .
when i tried to use these commands

Code:

---

        for (int i=0;i<9;i++)
            {
                  memory[4][i]=str[i];
       
            }

---

, the application compiles fine , without any error, but at runtime it crashes! so far i explained post 23 . and 24
now why C Style null terminated string ! because to me they are easier to manipulate . i can convert them to integer if needed (using atoi() , which i cant use string str sytle ) and i can point to any element of it , whenever i want to ( using *(ptr+counter) ) while i cant use string str format !

see to me C Style strings are awesome , I as a rookie dont need to do stuffs the hard way and get stuck in the middle of the way ! and you know thats because i dont know much about C++ and its strings . (and sadly im on a project that needs these knowledge ! ).

now , i used that string str format , and i need to copy the stuff at least to another string that can be subscripted!(like string str2[10]) .

hope it is clearer now .
(and most of the strings manipulations are done using C Style strings in my project so far ) .

Quote:

---

Originally Posted by Masterx

well, in post 23 and 24 im saying that because i declared str as "string str" i couldnt use subscripting to point to each elements of str and then copying them to another string .

---

Why do you need to point to the elements of the string? You certainly will not use subscript notation for that, even with a C style null terminated string. To copy to another std::string, just use assignment (unless you have more specific requirements).

Quote:

---

Originally Posted by Masterx

i can convert them to integer if needed (using atoi() , which i cant use string str sytle )

---

You can use a string stream, or you can use atoi() (or better yet, strtol()) via the c_str() member function.

Quote:

---

Originally Posted by Masterx

and i can point to any element of it , whenever i want to ( using *(ptr+counter) ) while i cant use string str format !

---

*(ptr+counter) is the long form of ptr[counter], which is the same syntax provided by std::string. You would be getting the char at the given index, not pointing to an element.

Quote:

---

Originally Posted by Masterx

see to me C Style Pointers are awesome

---

I have my doubts, considering that you apparently were not aware that ptr[counter] is syntactic sugar for *(ptr+counter).

Quote:

---

Originally Posted by laserlight

Why do you need to point to the elements of the string? You certainly will not use subscript notation for that, even with a C style null terminated string. To copy to another std::string, just use assignment (unless you have more specific requirements).


You can use a string stream, or you can use atoi() (or better yet, strtol()) via the c_str() member function.


*(ptr+counter) is the long form of ptr[counter], which is the same syntax provided by std::string. You would be getting the char at the given index, not pointing to an element.


I have my doubts, considering that you apparently were not aware that ptr[counter] is syntactic sugar for *(ptr+counter).

---

i use subscript notation because i do need to transfer the converted offsets to the memory which is a 2D array (Memory[row][i]) . see the memory should contain instruction in this way for example :
instruction MIX offset
row 1101 010 000 000 000
instruction and MIX is already feeded to the memory using subscript notations , and i dont use subscript notation, what should i use instead ?

and i use *(ptr+counter ) because i encountered problem using ptr[counter], i really dont know why , but that form didnt help me in some situations! but this *(ptr+counter) stuff works fine eachtime i use it. !

and about string streams . unluckily i dont know about them :( the same thing goes to strtol() and c_str() ) . :(

by the way does it work if i try to copy a string to another string with different forms! i mean suppose i have the following :
string str = " HEllO WORLD";
string str1[15];
does this workout? i mean "str1=str;"
(no i just gave it a try , doest work! it says" incompatible types in assignment of `std::string' to `std::string[15]'"
so in this case what should i do ?

Quote:

---

Originally Posted by Masterx

i dont use subscript notation, what should i use instead ?

---

My point is that you need to be clear on what you are talking about. You talked about using subscript notation to point to an element, but that is wrong. Normally, you use subscript notation to access an element at some index. You might go on to take the address of that element and make a pointer point to it, but that is not directly related to the use of subscript notation.

Quote:

---

Originally Posted by Masterx

and i use *(ptr+counter ) because i encountered problem using ptr[counter], i really dont know why , but that form didnt help me in some situations! but this *(ptr+counter) stuff works fine eachtime i use it. !

---

You probably accidentally made a genuine fix while changing to the *(ptr+counter) notation. When ptr is a pointer and counter is an index (or vice versa, but that would not make as much sense), *(ptr+counter) is always equivalent to ptr[counter] (and also equivalent to counter[ptr], but that would be misleading).

Quote:

---

Originally Posted by Masterx

and about string streams . unluckily i dont know about them the same thing goes to strtol() and c_str() ) .

---

Search the Friendly Web. For example, cppreference.com has some material on them.

EDIT:

Quote:

---

Originally Posted by Masterx

by the way does it work if i try to copy a string to another string with different forms! i mean suppose i have the following :
string str = " HEllO WORLD";
string str1[15];
does this workout? i mean "str1=str;"

---

str is a std::string, str1 is an array of 15 std::string objects.

Quote:

---

Originally Posted by Masterx

so in this case what should i do ?

---

You need to decide on what you want to do.

Quote:

---

Originally Posted by laserlight

My point is that you need to be clear on what you are talking about. You talked about using subscript notation to point to an element, but that is wrong. Normally, you use subscript notation to access an element at some index. You might go on to take the address of that element and make a pointer point to it, but that is not directly related to the use of subscript notation.


You probably accidentally made a genuine fix while changing to the *(ptr+counter) notation. When ptr is a pointer and counter is an index (or vice versa, but that would not make as much sense), *(ptr+counter) is always equivalent to ptr[counter] (and also equivalent to counter[ptr], but that would be misleading).


Search the Friendly Web. For example, cppreference.com has some material on them.

EDIT:

str is a std::string, str1 is an array of 15 std::string objects.


You need to decide on what you want to do.

---

Quote:

---

you use subscript notation to access an element at some index

---

yes thats it , im trying to access an element ! sorry i couldnt convey it sooner!

well you are the pro here , if you say that , ok . i will use that .

and searchin , tanx , ill do it .

but

Quote:

---

str is a std::string, str1 is an array of 15 std::string objects.

---

if i need to copy this to that, how is it possible then ? a couple of copying functions i read about , couldnt help this one !!

Quote:

---

Originally Posted by Masterx

if i need to copy this to that, how is it possible then ?

---

As I said, you need to decide on what you want to do. For example, do you want to set each element of the string array to be a copy of the initial string?

Quote:

---

Originally Posted by laserlight

As I said, you need to decide on what you want to do. For example, do you want to set each element of the string array to be a copy of the initial string?

---

yes . i mean that.

Quote:

---

Originally Posted by Masterx

yes . i mean that.

---

In that case, a simple method would be to use a loop:

Code:

---

std::string str = "hello world";
std::string str_array[15];
const std::size_t str_array_size = sizeof(str_array) / sizeof(str_array[0]);

for (std::size_t i = 0; i < str_array_size; ++i)
{
    str_array[i] = str;
}

---

A more succinct method would be to #include <algorithm> and use std::fill(), e.g.,

Code:

---

std::fill(str_array, str_array + str_array_size, str);

---

or std::fill_n(), e.g.,

Code:

---

std::fill_n(str_array, str_array_size, str);

---

In the context of your earlier question about converting a numeric string in octal representation to a numeric string in binary representation a loop would probably be good enough.

Quote:

---

Originally Posted by Masterx

and about string streams . unluckily i dont know about them :( the same thing goes to strtol() and c_str() ) . :(

---

I believe I already showed you an example on how to use string streams, no?

As for .c_str():

Code:

---

std::string str = "10";
long x = strtol(str.c_str());

---

Or if you want:

Code:

---

std::string str = "10";
long x = boost::lexical_cast<long>(str);

---

The second example works to convert a given type to any type, so long as that conversion is supported and possible. You don't need to remember 5 or more functions to do a conversion. Just one.

Quote:

---

Originally Posted by laserlight

In that case, a simple method would be to use a loop:

Code:

---

std::string str = "hello world";
std::string str_array[15];
const std::size_t str_array_size = sizeof(str_array) / sizeof(str_array[0]);

for (std::size_t i = 0; i < str_array_size; ++i)
{
    str_array[i] = str;
}

---

A more succinct method would be to #include <algorithm> and use std::fill(), e.g.,

Code:

---

std::fill(str_array, str_array + str_array_size, str);

---

or std::fill_n(), e.g.,

Code:

---

std::fill_n(str_array, str_array_size, str);

---

In the context of your earlier question about converting a numeric string in octal representation to a numeric string in binary representation a loop would probably be good enough.

---

many tanx dear laserlight . really tanx .

Quote:

---

Originally Posted by Elysia

I believe I already showed you an example on how to use string streams, no?

As for .c_str():

Code:

---

std::string str = "10";
long x = strtol(str.c_str());

---

Or if you want:

Code:

---

std::string str = "10";
long x = boost::lexical_cast<long>(str);

---

The second example works to convert a given type to any type, so long as that conversion is supported and possible. You don't need to remember 5 or more functions to do a conversion. Just one.

---

tanx dear alysia , no you didnt give me any examples ( i think) .
but thanks again . now its fine ...

------------------------------
now the function works just fine . thank you all ( i used all of copy functions you ve told me , to remember them :d
octal to binary convertor

Code:

---

#include <cstdlib>
#include <iostream>
#include <cstdio>
#include <string>
using namespace std;
  // Octal to binary convertor
string Oct2Bin(int);


int main(int argc, char *argv[])
{
        int b,i=0,j=0;
        char memory[5][10];
        char * str2,*ptr;
        string str;



        cout<<"enter a number ";
        cin>>b;

        str=Oct2Bin(b);

        ptr = new char [str.size()+1];
        strcpy (ptr, str.c_str());

        cout<<ptr<<endl;
        if (str=="no")
        {
                      cout<<"not an octal number\n";
        }
        cout<<str<<endl;

        system("PAUSE");
        return EXIT_SUCCESS;

}

string Oct2Bin(int n)
{


        int a[6],i=0,t=0,num;
        string str,str1,str2,s;

        char buffer[9];
        char * ptr, * not_octal;
        string str_array[9];
        const size_t str_array_size = sizeof(str_array) / sizeof(str_array[0]);

        while(n!=0)
        {
                a[i]=n%10;
                n=n/10;
                if(a[i]>7)
                t=1;
                i++;
        }
        i--;
        if(t==0)
          for(;i>=0;i--)
          {
                  switch(a[i])
                  {
                          case 0:
                          if (!str.empty())
                          str.append("000");
                          else
                          str="000";
                          break;

                          case 1:
                          if (!str.empty())
                          str.append("001");
                          else
                          str="001";
                          break;

                          case 2:
                          if (!str.empty())
                          str.append("010");
                          else
                          str="010";
                          break;

                          case 3:
                          if (!str.empty())
                          str.append("011");
                          else
                          str="011";
                          break;

                          case 4:
                          if (!str.empty())
                          str.append("100");
                          else
                          str="100";
                          break;

                          case 5:
                          if (!str.empty())
                          str.append("101");
                          else
                          str="101";
                          break;

                          case 6:
                          if (!str.empty())
                          str.append("110");
                          else
                          str="110";
                          break;

                          case 7:
                          if (!str.empty())
                          str.append("111");
                          else
                          str="111";
                          break;
                  }
          }
          str1="000000";
          str2="000";
              if (str.length()==3)
              {
                        str1.append(str);
                        str=str1;
              }

              if (str.length()==6)
              {
                        str2.append(str);
                        str=str2;
              }


        for (size_t i = 0; i < str_array_size; ++i)
        {
                  str_array[i] = str;
        }

          ptr = new char [str.size()+1];
          strcpy (ptr, str.c_str());

          //cout<<ptr;
        if(t==1)
          {
                 
                  s="no";
                // cout<<"Not a Octal number\n";
                return s;
          }
return str;
}

---

Actually, I did. Refer to post #13.

Quote:

---

Originally Posted by Elysia

Actually, I did. Refer to post #13.

---

yeah , my bad , i forgot about that when i was googling ? my apologies.

thanks again from you all Great mates.