Changing Javascript variable with function?

Question

I was able to do it with the var computerChoice = Math.random(); … and turning that variable into rock, paper or scissors… but now I can't get the variable 'winner' to change so that it prints out the results. It just keeps printing out 'undefined'. Help?

 var choice1 = userChoice;
 var choice2 = computerChoice;


 var winner = "undefined";


 var compare = function (choice1, choice2) {//start function

     if (choice1 === choice2) {
         winner = "Tie game!";


     } else if (choice1 === "rock") {
         if (choice2 === "scissors") {
             winner = "rock wins";
         } else {
             winner = "paper wins";
         }
     } else if (choice1 === "paper") {
         if (choice2 === "rock") {
             winner = "paper wins";
         } else {
             winner = "scissors wins";
         }
    } else {
        if (choice2 === "paper") {
            winner = "scissors wins";
        } else {
            winner = "rock wins";
        }
    }

}//end function


confirm("You chose: " + userChoice + "\nSystem: " + computerChoice + "\nOutcome: " + winner);


compare(userChoice,computerChoice);

</script>

please use a switch instead the ifs it will make your code look better easier to read — Dalorzo
– Dalorzo, Commented May 9, 2016 at 20:52

Mike Cluck · Accepted Answer · 2016-05-09 20:51:39Z

2

That's because you aren't changing it before you display it. Call compare before you call confirm since compare is the function that changes winner.

compare(userChoice, computerChoice);
confirm("You chose: " + userChoice + "\nSystem: " + computerChoice + "\nOutcome: " + winner);

answered May 9, 2016 at 20:51

Mike Cluck

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Comments

Simon Schüpbach · Accepted Answer · 2016-05-09 20:53:26Z

0

You should change the order of the function calls.

compare(userChoice,computerChoice);
confirm("You chose: " + userChoice + "\nSystem: " + computerChoice + "\nOutcome: " + winner);

answered May 9, 2016 at 20:53

Simon Schüpbach

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Comments

Bassam Rubaye · Accepted Answer · 2016-05-09 21:30:53Z

You can put 'confirm' inside the 'compare' function block and delete all of these global variables

choice1 ,userChoice; choice2 , computerChoice;

     var compare = function (choice1, choice2) {//start function

         var winner; //you don't need to specify 'undefined'

         if (choice1 === choice2) {
             winner = "Tie game!";


         } else if (choice1 === "rock") {
             if (choice2 === "scissors") {
                 winner = "rock wins";
             } else {
                 winner = "paper wins";
             }
         } else if (choice1 === "paper") {
             if (choice2 === "rock") {
                 winner = "paper wins";
             } else {
                 winner = "scissors wins";
             }
        } else {
            if (choice2 === "paper") {
                winner = "scissors wins";
            } else {
                winner = "rock wins";
            }
        }

confirm("You chose: " + choice1+ "\nSystem: " + choice2+ "\nOutcome: " + winner);

    }//end function

Keep in mind keeping your variables locals to a scope better than globals

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