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Engineering LibreTexts

5.14: JavaScript Examples

  • Page ID
    10667
  • Temperature

    // This program displays a temperature conversion table showing Fahrenheit
    // temperatures from 0 to 100, in increments of 10, and the corresponding 
    // Celsius temperatures using While, Do While, and For loops.
    //
    // References:
    //   https://www.mathsisfun.com/temperature-conversion.html
    //   https://en.wikibooks.org/wiki/JavaScript
    
    main();
    
    function main() {
        whileLoop();
        doLoop();
        forLoop();
    }
    
    function whileLoop() {
        var fahrenheit;
        var celsius;
        
        displayHeading();
        fahrenheit = 0;
        while (fahrenheit <= 100) {
            celsius = calculateCelsius(fahrenheit);
            displayResult(fahrenheit, celsius);
            fahrenheit += 10;
        }
        output("");
    }
    
    function doLoop() {
        var fahrenheit;
        var celsius;
        
        displayHeading();
        fahrenheit = 0;
        do {
            celsius = calculateCelsius(fahrenheit);
            displayResult(fahrenheit, celsius);
            fahrenheit += 10;
        } while (fahrenheit <= 100);
        output("");
    }
    
    function forLoop() {
        var fahrenheit;
        var celsius;
        
        displayHeading();
        for (fahrenheit = 0 ; fahrenheit <= 100 ; fahrenheit += 10) {
            celsius = calculateCelsius(fahrenheit);
            displayResult(fahrenheit, celsius);
        }
        output("");
    }
    
    function displayHeading() {
        output("F°\tC°");
    }
    
    function calculateCelsius(fahrenheit) {
        var celsius;
    
        celsius = (fahrenheit - 32) * 5 / 9;
    
        return celsius;
    }
    
    function displayResult(fahrenheit, celsius) {
        output(fahrenheit.toString() + "\t" + celsius.toString());
    }
    
    // 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

    F°	C°
    0	-17.77777777777778
    10	-12.222222222222221
    20	-6.666666666666667
    30	-1.1111111111111112
    40	4.444444444444445
    50	10
    60	15.555555555555555
    70	21.11111111111111
    80	26.666666666666668
    90	32.22222222222222
    100	37.77777777777778
    
    F°	C°
    0	-17.77777777777778
    10	-12.222222222222221
    20	-6.666666666666667
    30	-1.1111111111111112
    40	4.444444444444445
    50	10
    60	15.555555555555555
    70	21.11111111111111
    80	26.666666666666668
    90	32.22222222222222
    100	37.77777777777778
    
    F°	C°
    0	-17.77777777777778
    10	-12.222222222222221
    20	-6.666666666666667
    30	-1.1111111111111112
    40	4.444444444444445
    50	10
    60	15.555555555555555
    70	21.11111111111111
    80	26.666666666666668
    90	32.22222222222222
    100	37.77777777777778