FunctionalCalculator

function calc(a, b, operator) {
    "use strict";

    if (operator == '+') {
        console.log(a + b);
    }

    else if (operator == '-') {
        console.log(a - b);
    }

    else if (operator == '/') {
        console.log(a / b);
    }

    else if (operator == '*') {
        console.log(a * b);
    }
}