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Engineering LibreTexts

6.14: JavaScript Examples

  • Page ID
    10684
  • Arrays

    // This program demonstrates array processing, including:
    // display, total, max, min, parallel arrays, sort
    // multidimensional arrays, and dynamic arrays.
    
    main()
    
    function main() {
        var names = ['Lisa', 'Michael', 'Ashley', 'Jacob', 'Emily'];
        var ages = [49, 48, 26, 19, 16];
    
        displayArray(names);
        displayArray(ages);
    
        var total = sum(ages);
        var maximum = max(ages);
        var minimum = min(ages);
    
        output('total: ' + total);
        output('maximum: ' + maximum);
        output('minimum: ' + minimum);
    
        displayParallel(names, ages);
    
        ages.sort();
        displayArray(ages);
    
        displayMultidimensional();
        dynamicArray();
    }
    
    function displayArray(array) {
        for (var index = 0; index < array.length; index++) {
            output('array[' + index + '] = ' + array[index]);
        }
    }
    
    function sum(array) {
        var total = 0;
        for (var index = 0; index < array.length; index++) {
            total += array[index];
        }
        return total;
    }
    
    function max(array) {
        var maximum = array[0];
        for (var index = 1; index < array.length; index++) {
            if (maximum < array[index]) {
                maximum = array[index];
            }
        }
        return maximum;
    }
    
    function min(array) {
        var minimum = array[0];
        for (var index = 1; index < array.length; index++) { if (minimum > array[index]) {
                minimum = array[index];
            }
        }
        return minimum;
    }
    
    function displayParallel(names, ages) {
        for (var index = 0; index < names.length; index++) {
            output(names[index] + ' is ' + ages[index] + ' years old');
        }
    }
    
    function displayMultidimensional() {
        var game = [
            ['X', 'O', 'X'], 
            ['O', 'O', 'O'], 
            ['X', 'O', 'X'] ];
    
        for (var row = 0; row < 3; row++) {
            var line = '';
            for (var column = 0; column < 3; column++) {
                line += game[row][column];
                if (column < 2) {
                    line += ' | ';
                }
            }
            output(line);
        }
    }
    
    function dynamicArray() {
        var array = []
    
        for (var index = 0; index < 5; index++) {
            var number = Math.floor(Math.random() * 100);
            array.push(number);
        }
        displayArray(array);
    }
    
    // Checks the JavaScript environment and writes to the console, 
    // the current document, or standard output as appropriate.
    // Reference: http://progopedia.com/example/hello-world/114/ 
    function output(text) {
        if (typeof console === 'object') {
            console.log(text);
        } 
        else if (typeof document === 'object') {
            document.write(text);
        } 
        else {
            print(text);
        }
    }
    

    Output

    array[0] = Lisa
    array[1] = Michael
    array[2] = Ashley
    array[3] = Jacob
    array[4] = Emily
    array[0] = 49
    array[1] = 48
    array[2] = 26
    array[3] = 19
    array[4] = 16
    total: 158
    maximum: 49
    minimum: 16
    Lisa is 49 years old
    Michael is 48 years old
    Ashley is 26 years old
    Jacob is 19 years old
    Emily is 16 years old
    array[0] = 16
    array[1] = 19
    array[2] = 26
    array[3] = 48
    array[4] = 49
    X | O | X
    O | O | O
    X | O | X
    array[0] = 30
    array[1] = 97
    array[2] = 87
    array[3] = 42
    array[4] = 40