String Length function

Hi everyone, I have been learning about strings and successfully wrote my first string program which counts the characters in a given sentence. The problem that I ran into was that I wanted the program to count a string of characters that was entered by the user (no matter what it was)
e.g.
My name is Glenn
output: 16 (including spaces)

This is the program I was able to successfully run

Code:

#include<iostream.h>
#include<cstring>

int main()
{
char *string_a= "This is a test";

cout<<"The length of \""<<string_a<<"\"is "<<strlen (string_a)<<endl;

return 0;
}

This is the program that I am trying to write so that it returns the number of characters input by the user

Code:

#include<iostream.h>
#include<cstring>

int main()
{
char *string;

cout<<"What is your string";
cin>>string;

cout<<" The length of "<<string<<" is " << strlen (string)<<endl;

return 0;
}

I thought that the program was written correctly because it returns no (compiling) error but when it compiles Visual C returns an error and closes my program out.


Can someone please poing me in the right direction....Should I start over??

Thank you very much

char *string;
cout<<"What is your string";
cin>>string;

You need to allocate space for your pointer
Easy suggestion is to start with
char string[100];

If you're including the string library, why not just use string variables instead of char arrays?

#include<cstring> - For c style string manipulation like strlen, strcat, strcmp - the new version of <string.h>.
#include<string.h> - Deprecated version of <cstring>.
#include<string> - For the standard string class (std::string).

Even though you aren't actually including the string library, I would definitely agree with joshdick to use the standard string class. Also, why do you use the old <iostream.h> but the new <cstring>? Just stick to the new headers (e.g. <iostream>).

And finally, if for some reason you do need to use c-style strings, I would add to Salem's advice by protecting the input so that it won't overflow using setw.

[Edit: See later post for solution that better solves the OP's problem (this one ignores the inclusion of space characters in the string).]

So here is my preferred solution:

Code:

#include<iostream>
#include<string>

int main()
{
    std::string string_a;

    std::cout<<"What is your string: ";
    std::cin>>string_a;

    std::cout<<" The length of "<<string_a<<" is " << string_a.length()<<std::endl;

    return 0;
}

And here is a solution with c style strings:

Code:

#include<iostream>
#include<cstring>
#include<iomanip>

int main()
{
    char string_a&#091;100&#093;;

    std::cout<<"What is your string: ";
    std::cin>>std::setw(100)>>string_a;

    std::cout<<" The length of "<<string_a<<" is " << strlen (string_a)<<std::endl;

    return 0;
}

Thanks for clearing that up for me, jlou.

Sorry, I didn't notice that you really want the input with the spaces. Here are the two pieces of code above corrected to accept the entire line.

Preferred using standard string:

Code:

#include<iostream>
#include<string>

int main()
{
    std::string string_a;

    std::cout<<"What is your string: ";
    std::getline(std::cin, string_a);

    std::cout<<" The length of \""<<string_a<<"\" is " << string_a.length()<<std::endl;

    return 0;
}

And using c-style strings:

Code:

#include<iostream>
#include<cstring>

int main()
{
    char string_a&#091;100&#093;;

    std::cout<<"What is your string: ";
    std::cin.getline(string_a, 100);

    std::cout<<" The length of \""<<string_a<<"\" is " << strlen (string_a)<<std::endl;

    return 0;
}

Hi everyone, I just wanted to say thanks for the help. I was able to clean up my code and run it successfully.

Thanks