Ошибка - ISO C++ forbids comparison between pointer and integer

Пробую скомпилировать код:

// Calculator

#include <iostream>

using namespace std;

int main()
{
    float num1, num2, result;
    char action;

    cout << "What are we going to do? (+, -, *, /): ";
    cin >> action;

    cout << "Enter 1-st number: ";
    cin >> num1;
    cout << "Enter 2-nd number: ";
    cin >> num2;

    if (action == "+") {
        result = num1 + num2;
        cout << "Result is: " << result;
    }

    if (action == "-") {
        result = num1 - num2;
        cout << "Result is: " << result;
    }

    return 0;
}

Выдает ошибку:

error: ISO C++ forbids comparison between pointer and integer [-fpermissive]

Подскажите, как исправить?