Simple if condition with strings [duplicate]

Question

Possible Duplicate:
How do I properly compare strings in C?

#include <iostream>
using namespace std;

int main(){

    char name[100];
    cout<<"Enter: ";
    cin>>name;
    if(name == "hello"){
        cout<<"Yes it works!";
    }

    return 0;
}

Why when I entered hello in the prompt i didnt got "Yes it works!" message?

Answer 1

You need to use strcmp to test for equality.

name is an array, not a std::string, and hello is a string literal, i.e. a const char*. You're comparing pointers, not strings.

Answer 2

Try this:

#include <string.h>
#include <iostream>
using namespace std;

int main(){

    char name[100];
    cout<<"Enter: ";
    cin>>name;

    if(strcmp(name, "hello") == 0) {
        cout << "Yes it works!"; 
    }

    return 0; 
} 

Answer 3

If you use std::string instead of a char array, it will work:

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

int main(){

    string name;
    cout<<"Enter: ";
    cin>>name;
    if(name == "hello"){
        cout<<"Yes it works!";
    }

    return 0;
}

Answer 4

There are low-level strings ("C strings") which do not have the high-level behaviors you have probably come to expect from other languages. When you type in a string literal (in "quotes") you are creating one of those types of strings:

http://en.wikipedia.org/wiki/C_string_handling

In C++, one of the first things people do is pass that low-level string to the constructor of std::string to create an instance of a class that has more of the conveniences in interface that you would be used to.

http://www.cplusplus.com/reference/string/string/

Because C++ is layered over a very C-like foundation, it's valuable to understand how C-style strings work. At the same time, a professional/idiomatic C++ program should not use functions like strcmp. For an interesting study into the differences between C style programming and C++ style programming, check this out:

Learning Standard C++ As A New Language (PDF) by Bjarne