Programming Fundamentals/Variable Examples JavaScript

Overview

The following examples demonstrate data types, arithmetic operations, and input in JavaScript.

Data Types

// This program demonstrates variables, literal constants, and data types.varn;vars;varb;n=1.23456789012345;s="string";b=true;output("Number n = "+n);output("String s = "+s);output("Boolean b = "+b);functionoutput(text){if(typeofdocument==='object'){document.write(text);}elseif(typeofconsole==='object'){console.log(text);}else{print(text);}}

Output

Number n = 1.23456789012345 String s = string Boolean b = true 

Discussion

Each code element represents:

• • // begins a comment
  • var n, s, and b define variables
  • ; ends each line of JavaScript code
  • i = , d = , s =, b = assign literal values to the corresponding variables
  • output() calls the output function
  • function output(text) defines a output function that checks the JavaScript environment and writes to the current document, the console, or standard output as appropriate.

Arithmetic

// This program demonstrates arithmetic operations.vara;varb;a=3;b=2;output("a = "+a);output("b = "+b);output("a + b = "+(a+b));output("a - b = "+(a-b));output("a * b = "+a*b);output("a / b = "+a/b);output("a % b = "+(a%b));functionoutput(text){if(typeofdocument==='object'){document.write(text);}elseif(typeofconsole==='object'){console.log(text);}else{print(text);}}

Output

a = 3 b = 2 a + b = 5 a - b = 1 a * b = 6 a / b = 1.5 a % b = 1 

Discussion

Each new code element represents:

• +, -, *, /, and % represent addition, subtraction, multiplication, division, and modulus, respectively.

Temperature

// This program converts an input Fahrenheit temperature to Celsius.varfahrenheit;varcelsius;output("Enter Fahrenheit temperature:");fahrenheit=input();celsius=(fahrenheit-32)*5/9;output(fahrenheit.toString()+"° Fahrenheit is "+celsius+"° Celsius");functioninput(text){if(typeofwindow==='object'){returnprompt(text)}elseif(typeofconsole==='object'){constrls=require('readline-sync');varvalue=rls.question(text);returnvalue;}else{output(text);varisr=newjava.io.InputStreamReader(java.lang.System.in);varbr=newjava.io.BufferedReader(isr);varline=br.readLine();returnline.trim();}}functionoutput(text){if(typeofdocument==='object'){document.write(text);}elseif(typeofconsole==='object'){console.log(text);}else{print(text);}}

Output

Enter Fahrenheit temperature: 100 100° Fahrenheit is 37.7777777777778° Celsius 

Discussion

Each new code element represents:

• function input(text) defines a function that checks the JavaScript environment and reads from the current window, the console, or standard input as appropriate.

References

• Wikiversity: Computer Programming

Programming Fundamentals