5. Ten Simple JavaScript Exercises

Define a function sum() and a function multiply() that sums and multiplies (respectively) all the numbers in an array of numbers. For example, sum([1,2,3,4]) should return 10, and multiply([1,2,3,4]) should return 24.

by Lisa French

HTML

<h1>Ten Simple JavaScript Exercises</h1>

<a href="https://github.com/lisafrench/JavaScriptExercises">Read More Here</a> 
    
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<h3>JavaScript Exercise 5:</h3>

<p>
Define a function sum() and a function multiply() that sums and multiplies (respectively) all the numbers in an array of numbers. For example, sum([1,2,3,4]) should return 10, and multiply([1,2,3,4]) should return 24.
</p>

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<h3>Console Log Out:</h3>

<div id="console-log"></div>

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JavaScript

//Hack to mimic console within JSFiddle
var consoleLine = "<p class=\"console-line\"></p>";
console = {
    log: function (text) {
        $("#console-log").append($(consoleLine).html(text));
    }
};

//Begin exercise
var numbers = [1, 2, 3, 4];

function sum() {
    var total = 0;
    for (var i = 0; i < numbers.length; i++) {
        total += numbers[i];
    }
    return total;
}

function multiply() {
    //Setting total to one, since multiplying by zero will yeild zero
    var total = 1;
    for (var i = 0; i < numbers.length; i++) {
        total = total * numbers[i];
    }
    return total;
}
console.log('The summed result of ' + numbers + ' is: ' + '"' + sum() + '"');
console.log('The multiplied result of ' + numbers + ' is: ' + '"' + multiply() + '"');