Strcmp

I want to create a program that asks the user to input a word ,
then it searches the word in the given txt file. So far what i have been able to do is ,
i have used the getline function, to display the contents , then i have converted the std::string line
to c-string to get tokens ,now i want to compare these tokens with the word that the user entered,
but i dun know how.

Code:

---

#include <iostream>
#include <fstream>
#include <string>
#include <stdio.h>
#include <string.h>

using namespace std;



int main ()
{ 
          char *                          cstr;
        char *                          p;
        string                          line;
        fstream                  myfile;
        char delim[]          ="  :,.-;!?_-()";
        char                          arr[12];
       
        cout<<"Enter a word to check whether it is in the text file:";
        cin>>arr;





       
        myfile.open ("Ahoo.txt");

                  if (myfile.is_open())
                       
                        {
                                                 
                                while (!myfile.eof())
                 
                                        {
                                       
                                                getline (myfile,line);
                                                cstr = new char [line.size()+1];       
                                                strcpy (cstr, line.c_str());                                                                                       
                                                p=strtok (cstr,delim);                                                                                                       
                                                         
                                                        while (p!=NULL)
                                                            {
                                                            cout << p << endl;
                                                            p=strtok(NULL,delim);
                                                        }       

                                                delete[] cstr; 
                               
                                          }
                               
                                myfile.close();
                        }

                        else
                        {
                                cout<<"File not opened";
                        }
  return 0;
}

---

Are you just trying to get the job done (quick n dirty) or shooting for a more elegant solution?

I ll be thankful , if you tell me both of the ways.

Well two of the many ways of skinning this cat: (sips tea and wishes for IV):
Quick n Dirty:
1. Get word from user.
2. mmap file
3. for(position = 0; position < (fileSize - wordSize); position++)
4. if(memcmp(word, filePtr+position, wordSize)==0)
5. print "Match found, position is ", position

However if the quick n dirty solution isn't what your instructor is striving for then prepare to get your knuckles rapped. A more elegant search solution can be found here:

http://en.wikipedia.org/wiki/Boyer–M...arch_algorithm

However that may be what we call a 100 dollar solution to a 10-buck problem. It helps to know what your actual goal is.

You shouldn't mix C-strings with C++ std::string. Not that it is wrong, but why not use all the functionalities of std::string?

First of all, you can just use find() and do your job really quickly.

Code:

---

string str ("There are two needles in this haystack with needles.");
  string str2 ("needle");
  size_t found;

  // different member versions of find in the same order as above:
  found=str.find(str2);
  if (found!=string::npos)
    cout << "first 'needle' found at: " << int(found) << endl;

---

i was going through this example , but i didn't get the highlighted part of the code.

myfile.open (filename."txt");

I want the user to tell the file name , which the program will open , there is some error with this statement. if anyone can tell me how to write this.

I think everything you need to understand that code is on this page. If you read the whole page...

Quote:

---

Originally Posted by Fatima Rizwan

myfile.open (filename."txt");

---

Code:

---

myfile.open ("filename.txt");

---

You can use a variable in place of the file name

Quote:

---

Originally Posted by Fatima Rizwan

Code:

---

string str ("There are two needles in this haystack with needles.");
  string str2 ("needle");
  size_t found;

  // different member versions of find in the same order as above:
  found=str.find(str2);
  if (found!=string::npos)
    cout << "first 'needle' found at: " << int(found) << endl;

---

i was going through this example , but i didn't get the highlighted part of the code.

---

string::npos is just a constant integer defined somewhere (in the string class actually, that is why it starts with string::).
If find() doesn't find what you want, then found == string::npos. That is all.

As for open, indeed you can use a variable. Of type const char*. You could do this for example

Code:

---

cin >> str;
myfile.open(str.c_str());

---

Ok, thanks
Now if the given string is found in the file. I want to print all the attributes of that file.
Is there any function for this purpose?Any help!

Code:

---

#include <iostream>
#include <fstream>
#include <string>
#include <stdio.h>
#include <stdlib.h>
#include <io.h>
#include <time.h>

using namespace std;

class FileManipulator
{       
                string word;
                string name;

        public:

                void wordinput()
                {
                        cout<<"Enter word:";          cin>>word;
                }

                void nameinput()
                {
                        cout<<"Enter file:";        cin>>name;
                }

                string getname()
                {
                        return name;
                }

                void manipulation()
                {
                        fstream  my_file;               
                        string line;
                        int found;                       
                        string ext=".txt";
                       

                        my_file.open (getname()+ext);
                        {
                                if (my_file.is_open())
                       
                                {
                               
                                        while (!my_file.eof())
                                        {
               
                                                getline (my_file,line);
                                                found=line.find(word);
                                                       
                                                if (found != string::npos)
                                                {       
                                                        cout<<found;
                                                }
                                                else
                                                {
                                                        cout<<"NOT found";
                                                }
                                        }
                                        my_file.close();
                                }


                                else
                                {
                                        cout<<"File not opened";
                                }
                        }               
                }

                /*void printFile()
                         
                }*/

};

int main()
{
        FileManipulator f;
        f.wordinput();
        f.nameinput();
        f.manipulation();
        /*f.printFile();*/
        return 0;
}

---

Code:

---

while (!my_file.eof())
{

    getline (my_file,line);

    ...

}

---

This method of controlling loops by testing eof is error prone and rarely done correctly. It is recommended to test the read operation directly, getline in this case:

Code:

---

while ( getline(my_file,line) )
{

    ...

}

---

Code:

---

string getname()
{
    return name;
}

void manipulation()
{
    ...
}

---

Member functions that do not modify the class should be const:

Code:

---

string getname() const
{
    return name;
}

void manipulation() const
{
    ...
}

---

Code:

---

int found;                       

...

found=line.find(word);
                                                       
if (found != string::npos)

---

The find member function returns a value of type size_type:

Code:

---

string::size_type found;

...

found=line.find(word);
                                                       
if (found != string::npos)

---

Code:

---

#include <stdio.h>
#include <stdlib.h>
...
#include <time.h>

---

Prefer the newer versions of these header files where available:

Code:

---

#include <cstdio>
#include <cstdlib>
...
#include <ctime>

---

Code:

---

fstream  my_file;               
...
string ext=".txt";

...
                       
my_file.open (getname()+ext);

---

The fstream object's open member function does not accept string arguments (currently). You need to use the c_str member function to convert the string container into something it does accept. (Has this changed yet?)

Code:

---

my_file.open ((getname()+ext).c_str());

---

I have made the amendments now if I have found the word required in file, i want to output its attributes. like file name, its location , time it was creatd , its size etc. Kindly help me with this.

What OS are you using? There are several options. A possible Windows/Microsoft solution could use functions such as GetFileAttributes. For other OS's others would need to point you to appropriate functions.

Look up stat() and friends if you are on a *NIX OS; POSIX has a whole raft of ops that can answer these questions...

Quote:

---

Originally Posted by jeffcobb

Look up stat() and friends if you are on a *NIX OS; POSIX has a whole raft of ops that can answer these questions...

---

and also on Windows. Although Microsoft prefers to call it _stat() instead. :rolleyes:
Most of those POSIX functions start with _ on Windows.

Code:

---

string* getFname()
                {
               
                        if((hfile=_findfirst("C:/tr1/*.txt",&c_file))==-1)
                        {}
                       
                        else
                        {
                int position=0;
                                str[0]=c_file.name;
                                position++;
                       
                                while(_findnext(hfile,&c_file)==0);
                                {                               
                                        str[position]=c_file.name;
                                        position++;
                                }
                        }
                        return str;
                }

---

this functions searches for all the text files in the particular folder and returns their name in string pointer.

Code:

---

        int manipulation()        const
                {       
                        fstream  my_file;                        string line;
                        string::size_type found;       
                       
                        my_file.open ((file::getFname()).c_str());
                        {
                                if (my_file.is_open())
                                {
                                        while ( getline(my_file,line) )
                                        {
                                                found=line.find(word);
                                                if (found != string::npos){                return found;                        }
                                                /*if (found == string::npos){        cout<<"NOT found"<<endl; }*/
                                        }
                                        my_file.close();
                                }
                                else        { cout<<"File not opened";        }
                        }               
                }

---

this files then uses the name of the file and do the manipulations i.e searches for the word in the file . I dont know how to deal with the pointers .The higlighted part of code is giving me errors.
cannot convert 'this' pointer from 'const FileManipulator' to 'file &'