JavaScript Examples
Dave Braunschweig
Temperature
// This program asks the user to select Fahrenheit or Celsius conversion // and input a given temperature. Then the program converts the given // temperature and displays the result. // // References: // https://www.mathsisfun.com/temperature-conversion.html // https://en.wikibooks.org/wiki/JavaScript main(); function main() { // main could either be an if-else structure or a switch-case structure var choice; var temperature; var result; choice = getChoice(); // if-else approach if (choice == "C" || choice == "c") { temperature = getTemperature("Fahrenheit"); result = calculateCelsius(temperature); displayResult(temperature, "Fahrenheit", result, "Celsius"); } else if (choice == "F" || choice == "f") { temperature = getTemperature("Celsius"); result = calculateFahrenheit(temperature); displayResult(temperature, "Celsius", result, "Fahrenheit"); } else { output("You must enter C to convert to Celsius or F to convert to Fahrenheit!"); } // switch-case approach switch(choice) { case 'C': case 'c': temperature = getTemperature("Fahrenheit"); result = calculateCelsius(temperature); displayResult(temperature, "Fahrenheit", result, "Celsius"); break; case 'F': case 'f': temperature = getTemperature("Celsius"); result = calculateFahrenheit(temperature); displayResult(temperature, "Celsius", result, "Fahrenheit"); break; default: output("You must enter C to convert to Celsius or F to convert to Fahrenheit!"); } } function getChoice() { var choice; output("Enter C to convert to Celsius or F to convert to Fahrenheit:"); choice = input(); return choice; } function getTemperature(label) { var temperature; output("Enter " + label + " temperature:"); temperature = input(); return temperature; } function calculateCelsius(fahrenheit) { var celsius; celsius = (fahrenheit - 32) * 5 / 9; return celsius; } function calculateFahrenheit(celsius) { var fahrenheit; fahrenheit = celsius * 9 / 5 + 32; return fahrenheit; } function displayResult(temperature, fromLabel, result, toLabel) { output(temperature.toString() + "° " + fromLabel + " is " + result + "° " + toLabel); } function input(text) { if (typeof window === 'object') { return prompt(text) } else if (typeof console === 'object') { const rls = require('readline-sync'); var value = rls.question(text); return value; } else { output(text); var isr = new java.io.InputStreamReader(java.lang.System.in); var br = new java.io.BufferedReader(isr); var line = br.readLine(); return line.trim(); } } function output(text) { if (typeof document === 'object') { document.write(text); } else if (typeof console === 'object') { console.log(text); } else { print(text); } }
Output
Enter C to convert to Celsius or F to convert to Fahrenheit: c Enter Fahrenheit temperature: 100 100° Fahrenheit is 37.77777777777778° Celsius Enter C to convert to Celsius or F to convert to Fahrenheit: f Enter Celsius temperature: 100 100° Celsius is 212° Fahrenheit Enter C to convert to Celsius or F to convert to Fahrenheit: x You must enter C to convert to Celsius or F to convert to Fahrenheit.