C++ String Compare: Complete Guide

In C++, you can use the compare function of string to compare the sizes of two string objects. The prototype of this function is as follows:

int compare(const string& str) const;

When the function is invoked, it returns a negative value if the current string object is smaller than str, a positive value if the current string object is larger than str, and returns 0 if the two string objects are equal.

For example,

#include <iostream>
#include <string>

int main() {
    std::string str1 = "hello";
    std::string str2 = "world";

    if (str1.compare(str2) < 0) {
        std::cout << "str1 is less than str2" << std::endl;
    } else if (str1.compare(str2) > 0) {
        std::cout << "str1 is greater than str2" << std::endl;
    } else {
        std::cout << "str1 is equal to str2" << std::endl;
    }

    return 0;
}

The result of the operation is:

str1 is less than str2