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Java program to build a calculator

In this java program, we are writing code for a simple calculator. Here, we are performing multiple basic mathematical tasks using switch case statement and do while loop.
Submitted by IncludeHelp, on November 19, 2017

Problem statement

Given numbers and we have to perform mathematical operations using java program.

Java - Build a calculator

Here, we have following operations to be performed through this program,

1. Addition
2. Subtraction
3. Division
4. Multiplication
5. Exit

Program will run infinite times until we do not press the 5 (a user choice).

Program for simple mathematical operations (calculator) in java

import java.util.Scanner;

public class Calculator 
{
	public static void main(String args[])
	{
		// declare here
		float a,b,res;
		char choice, ch;
		Scanner S=new Scanner(System.in);
		
		do
		{
			// prepare menu for the user to see multiple operations.
			System.out.println("\n\nMain Menu : \n1.Addition\n2.Subtraction\n3.Division\n4.Multiplication\n5.Exit\n");
			
			// enter the choice
			System.out.print("Enter your choice : ");
			
			// read the input choice value.
			choice=S.next().charAt(0);
			
			// this loop will calculate different the operations value at different dofferent values.
			switch(choice)
			{ 
			    case '1':System.out.print("Enter two numbers : ");
			    a=S.nextFloat();
			    b=S.nextFloat();	
			    res=a+b;
			    System.out.print("Result : " +res);
			    break;
			     
			     case '2':System.out.print("Enter two numbers : ");
				 a=S.nextFloat();
				 b=S.nextFloat();	
				 res=a-b;
				 System.out.print("Result : " +res);
				 break;
				    
			     case '3':System.out.print("Enter two numbers : ");
				 a=S.nextFloat();
				 b=S.nextFloat();	
				 res=a/b;
				 System.out.print("Result : " +res);
				 break;
				    
			     case '4':System.out.print("Enter two numbers : ");
				 a=S.nextFloat();
				 b=S.nextFloat();	
				 res=a*b;
				 System.out.print("Result : " +res);
				 break;
				   
			     case '5':
				 System.exit(0);
				 break;
				 default : System.out.print("Wrong Choice.....\n");
				 break;
			}
	    }
		// loop works till the number 5 not selected.
	  while(choice!=5);
	}
}

Output

Main Menu : 
1.Addition
2.Subtraction
3.Division
4.Multiplication
5.Exit

Enter your choice : 1
Enter two numbers : 2 5
Result : 7.0

Main Menu : 
1.Addition
2.Subtraction
3.Division
4.Multiplication
5.Exit

Enter your choice : 2
Enter two numbers : 8 6
Result : 2.0

Main Menu : 
1.Addition
2.Subtraction
3.Division
4.Multiplication
5.Exit

Enter your choice : 3
Enter two numbers : 10 2
Result : 5.0

Main Menu : 
1.Addition
2.Subtraction
3.Division
4.Multiplication
5.Exit

Enter your choice : 4
Enter two numbers : 5 5
Result : 25.0

Main Menu : 
1.Addition
2.Subtraction
3.Division
4.Multiplication
5.Exit

Enter your choice : 5

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