Strings

**Sridar** · 09-19-2004

Ok...
I am a newbie here and i need to know how to do this

Code:

 
#include <iostream.h>

using namespace std;

int main()

{
    
   ????
    cout<<"Hi there! I am PC, the computer. What's your name?:";
    cin>>name;
    cout<<"Hello " <<name<< endl;
    
    std::cin.get();
    return 0;
}

Basically i'm trying to make the computer print the name that i input in there. Thing is i need to define "name", which is a string of letters

how do i do that?

**Perspective** · 09-19-2004

you have a few options, but first...
>> #include <iostream.h>
use: #include <iostream> instead

char name[SOME_MAXIMUM_SIZE];

or

#include <string>
string name;

**sean** · 09-19-2004

Code:

#include <iostream> // Notice that I excluded .h from the header file - see below

using namespace std;

int main()

{
    
    char name[20];
    cout<<"Hi there! I am PC, the computer. What's your name?:";
    cin>>name;
    cout<<"Hello " <<name<< endl;
    
    cin.get(); // You don't need std:: here
    return 0;
}

Although this will compile with a friendly compiler, it is correct to exclude the ".h" from your header inclusion. I'm assuming you're using up-to-date C++ since you included "using namespace std". This is also why you don't need std:: before your call to cin.get().

To declare, "name", you use an array of chars - this is called a C-style string. There are C++ strings, which are classes with functions, etc... but I used C-style strings here for a number of reasons, just so you know.

**Hunter2** · 09-19-2004

>>but I used C-style strings here for a number of reasons, just so you know.
Just out of curiosity, what are these reasons that you speak of? I mean, even Prelude thinks that beginners should start with C++ strings and then learn C-style later

**sean** · 09-19-2004

1) I'm more used to C-style strings

2) Useable in C and C++

3) Personally I thought C-style strings would be easier for newbies to grasp since they wouldn't have done much OOP yet, but I'm not one to argue with someone with as much knowledge of the language as Prelude.

**Vicious** · 09-19-2004

Code:

#include <iostream>
#include <string>

int main ( void )
{

    std::string name;

    std::cout << "What is your name: ";
    std::cin  >> name;

    // new line
    std::cout << std::endl;

    std::cout << name;

    return 0;

}

**AdamLAN** · 09-22-2004

Originally Posted by Sridar

Ok...
I am a newbie here and i need to know how to do this

Code:

 
#include <iostream.h>

using namespace std;

int main()

{
    
   ????
    cout<<"Hi there! I am PC, the computer. What's your name?:";
    cin>>name;
    cout<<"Hello " <<name<< endl;
    
    std::cin.get();
    return 0;
}

Basically i'm trying to make the computer print the name that i input in there. Thing is i need to define "name", which is a string of letters

how do i do that?

That should work, except for the ??????? part of the source code. Delete that, compile, and run. It should work fine.

**Hunter2** · 09-22-2004

>>Delete that, compile, and run. It should work fine.
In case you haven't noticed, he hasn't declared name. And he's using namespace std; with the <iostream.h> header. And there is no std::cin with the .h header. For a workine example, see vicious or sean's posts.

**Vicious** · 09-22-2004

Code:

#include <iostream>
#include <string>

using namespace std;

int main ()
{

	string name;

	cout << "Enter name: ";
	getline ( cin, name );

	cout << endl << name;      

	return 0;

}

Heres another example that will also read in spaces.

[edit]
If you use MSVC++ there might be a bug with getline.

fix it by editing line 165 of the file: c:\Program Files\Microsoft Visual Studio\VC98\Include\STRING

Line 165 should be:

_I.rdbuf()->sbumpc();

instead of:

_I.rdbuf()->snextc();

Thanks for hunter for the reminder!

**pizzapie** · 09-23-2004

i know your questions been answered but ill try to answer it again. To start with, you need a new tutorail. The one your using is out of date. i would suggest http://cplus.about.com you need to put in the library <string>. so you would put that just under #include <iostream>, remember that iostream.h and other .h header files are out of date. now you would declare a string just under

Code:

int main()
{

it should look like this

Code:

#include <iostream>
#include <string> // required for strings
using namespace std; // you should always have this
int main()
{
string name;
cout<<"Please enter your first name.";
cin>>name;
cout<<"Hello "<<name;

cin.ignore();
cin.get(); // no need for std before it, as you can see i also use cin.ignore, that is sometimes used 
// when cin.get doesn't work by itself, make sure you use it before cin.get, not after

return 0;
}

hope you get it

**Hermitsky** · 09-23-2004

personally, i think c++ strings is much easier to handle than C strings.

in the beginning was CppStrings
---------------------------Christian Bible,John 1:1
by Hermitsky 2004

**CornedBee** · 09-23-2004

Originally Posted by sean_mackrory

1) I'm more used to C-style strings

Can't argue with that. Oh, perhaps you should get more used to C++ strings.

2) Useable in C and C++

Which is really not an issue in a program that uses cout and cin.

3) Personally I thought C-style strings would be easier for newbies to grasp since they wouldn't have done much OOP yet, but I'm not one to argue with someone with as much knowledge of the language as Prelude.

It's not about knowledge of the language, it's about common sense. The C++ string behaves like a built-in type, it just makes sense. The C-style string doesn't.

Just a few examples. I'm assuming "using std::string". I want to put a string literal into a variable.

Code:

C++:
string str = "Hello, World!";
C:
const char *str = "Hello, World!"; /* What is "const char *"?
Why can't I say "char *"? The compiler allows it. Why can't I modify it? */
char str[] = "Hello, World!"; /* "char []"? Weird syntax. */

Yes, the syntax becomes second nature to C programmers, but newbies?

String copying with unknown size:

Code:

C++:
string str2 = str1;
C:
char *str2 = malloc(strlen(str1)+1);
strcpy(str2, str1);
/* And don't forget to free! */

Again, all those questions. What is malloc? What is strlen? Why can't I just say str2 = str1? Why do I have to remember to free? Why shouldn't I return such stuff from a function?

Concatenation:

Code:

C++:
str1 += str2;
C: (assuming that str1 was allocated with malloc)
char *t = malloc(strlen(str1)+strlen(str2)+1);
strcpy(t, str1);
strcat(t, str2);
free(str1);
str1 = t;

The code is getting longer.

There are more issues. Buffer sizes. Why do I have to watch for buffer overflows? What is that, anyway? Why can't I return a local buffer from a function?

And have you so far seen any signs of OOP in the C++ version? Anything that newbies would have to understand in order to use string? No, since it's a perfect blackbox. It might as well be built-in.

Bottom line: newbies usually want to do things now, and later learn the whys and hows. It's simply more fun that way.

**Hunter2** · 09-23-2004

All hail CornedBee!

Pizzapie:
>>using namespace std; // you should always have this
I beg to differ. For a more in-depth explanation, read this thread.

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