How to compare string with const char*?

Question

#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <string.h>
using namespace std;
int main()
{
        string cmd;
        while(strcmp(cmd.c_str(),"exit")==0 && strcmp(cmd.c_str(),"\exit")==0)
        {
                cin>>cmd;
                cout<<cmd;
        }
        return 0;
}

I am stuck.

Answer 1

A std::string instance can be compared directly with a string literal using != or == operators. This makes your comparison clearer.

Note that \e isn't a valid character escape, you need to double the \ if you meant a literal \\.

while( cmd == "exit" && cmd == "\\exit" )

Obviously cmd can't be equal to two different strings at the same time, presumably you meant !=.

Also, consider whether std::getline( std::cin, cmd ) is more appropriate than std::cin >> cmd;. In either case you should check for success of the read operation otherwise you may end in an infinite loop if the stream is closed or enters a failed state.

Personally I'd go with something like this, assuming that you want to echo the exit command as your code does.

#include <string>
#include <iostream>
#include <ostream>

int main()
{
    std::string cmd;
    while (std::getline(std::cin, cmd))
    {
        std::cout << cmd << std::endl;
        if (cmd == "exit" || cmd == "\\exit")
            break;
    }
    return 0;
}