How can I use Prompt, if and else in Javascript function to select arithmetic symbol and do some cal-CodePudding

I am a novice in this and it is really making me to lose my hair; I can find what I'm doing wrong, please help. I am doing this in javascript. It doesn't show any error, nor display any result either. This is what I have:

    var sumIt;
    var subtractIt;
    var multiplyIt;
    var divideIt;
    var operatorOpt = prompt("Select operator");
    
    function showResult(whatResult) {
        document.write(whatResult);
        document.write("<br>");
    }
    
    var doSomething = function(num1, num2) {
        if (operatorOpt == sumIt) {
            showResult("The result is: "   (num1   num2));
    
    
        } else if (operatorOpt == subtractIt) {
            showResult("The result is: "   (num1 - num2));
    
        }  else if (operatorOpt == multiplyIt) {
            showResult("The result is: "   (num1 * num2));
    
    
    }  else if (operatorOpt == divideIt) {
            showResult("The result is: "   (num1 / num2));
    
    doSomething(parseInt (prompt("Enter first number: ")) ,  parseInt (prompt("Enter second number: ")))

CodePudding user response：

Simply at the prompt create a list with the options like so:

    prompt("Select operator:" 
      "\n1. Addition" 
      "\n2.Subtraction" 
      "\n3.Multiplication" 
      "\n4.Division");

Then compare the user supplied numbers whit the operator number.

CodePudding user response：

It seems that your are missing a closed bracket in the definition of doSomething function. The following code seems to work produce the desired results

var sumIt = " ";
var subtractIt = "-";
var multiplyIt = "*";
var divideIt = "/";
var operatorOpt = prompt("Select operator");

function showResult(whatResult) {
    console.log(whatResult);
    document.write(whatResult);
    document.write("<br>");
}

var doSomething = function(num1, num2) {
    if (operatorOpt == sumIt) {
        showResult("The result is: "   (num1   num2));
    } else if (operatorOpt == subtractIt) {
        showResult("The result is: "   (num1 - num2));
    }  else if (operatorOpt == multiplyIt) {
        showResult("The result is: "   (num1 * num2));
    }  else if (operatorOpt == divideIt) {
        showResult("The result is: "   (num1 / num2));
    } else {
      console.log("No Condition reached");
    }

 }

 doSomething(parseInt (prompt("Enter first number: ")) ,  parseInt (prompt("Enter second number: ")));