If statement on args giving odd outputs

When running this code: ./a.out 5 + 5 i am supposed to get 10. but instead i get Unkown operator. does anyone know why this may be happening?

#include <iostream>
#include <string>
int main(int argc, char *argv[]){
    if (argv[2]=="+"){
        std::cout << std::stoi(argv[1])+std::stoi(argv[3]) << "\n";
    }
    else if (argv[2]=="-"){
        std::cout << std::stoi(argv[1])-std::stoi(argv[3]) << "\n";
    }
    else{
        std::cout << "Unkown operator." << "\n";
    }
    return 0;
}

>Solution :

This line is comparing pointer values, and not the strings data they point to…

    if (argv[2]=="+"){

Either use strcmp:

    if (strcmp(argv[2], "+") == 0){
    }

Or something along these lines:

    if (std::string(argv[2]) == "+"){
    }