Calculator Java class

Document Contents

In this post, we will learn how to create a Calculator Java class with simple features like add, subtract, multiply and divide methods. Later, we will learn how to test this class with JUnit framework.

Things you need

1.JDK installed on your computer.

2. IDE like Eclipse or IntelliJ.

(Note that you can also create a class using a source or text editor and
save with a .java file extension. This approach has several drawbacks. You tend
to know the disadvantages when you work with more than two classes.
So let’s use an IDE)

Steps to follow:

Create a Java Project

For example : Calculator Project

File >> New >> Project

Create a source package

For example: com.testingdocs.calculator

Create a class

src >> right click >> New >> Java class

Eclipse

IntelliJ IDEA

3.Create a Java class and name it Calculator

Calculator Java class

This class models some of the functions of a simple calculator which handles mathematical operations.

package com.testingdocs.calculator;
/**
* Calculator class:
* Basic Mathematical functions like
* Add,Subtract,Multiply,Divide.
*
*/
public class Calculator {
//no-arg constructor
public Calculator() {
}
/**
* Sum method.
*/
public int add(int a, int b) {
return a + b;
}
/**
* Subtract method.
*/
public int subtract(int a, int b) {
return a - b;
}

/**
* Multiply method.
*/
public long multiply(int a, int b) {
return a * b;
}

/**
* Divide method.
* Note that this method throws an exception when
* b is zero.
*/
public double divide(int a, int b) {
double result;
if (b == 0) {
throw new IllegalArgumentException("Divisor cannot divide by zero");
} else {
result = Double.valueOf(a)/Double.valueOf(b);
}
return result;
}
}