Simple Calculator Program in Java

This article covers multiple programs in Java, to create simple calculator. Here are the list of programs covered in this article:

  • Calculator program in Java using if else
  • Calculator program in Java using switch case - with infinite loop
  • Calculator program in Java using functions and switch case

Calculator Program in Java using if else

The question is, write a simple calculator program in Java that performs four basic arithmetic operations. The program given below is its answer:

import java.util.Scanner;

public class CodesCracker
{
   public static void main(String[] args)
   {
      float a, b, res;
      int choice;
      Scanner scan = new Scanner(System.in);
      
      System.out.println("1. Addition");
      System.out.println("2. Subtraction");
      System.out.println("3. Multiplication");
      System.out.println("4. Division");
      System.out.print("Enter Your Choice (1-4): ");
      choice = scan.nextInt();
      
      if(choice>=1 && choice<=4)
      {
         System.out.print("\nEnter any Two Number: ");
         a = scan.nextFloat();
         b = scan.nextFloat();
         
         if(choice==1)
            res = a+b;
         else if(choice==2)
            res = a-b;
         else if(choice==3)
            res = a*b;
         else
            res = a/b;
         
         System.out.println("\nResult = " +res);
      }
      else
         System.out.println("\nInvalid Choice!");
   } 
}

The snapshot given below shows the sample run of above program, with user input 4 as choice, 5 and 2 as two numbers, where 5 as first and 2 as second number:

calculator program in java using if else

Calculator Program in Java using switch

Here is another calculator program in Java created using switch case, instead of if...else. This program also continue its execution, until user enters 5 as choice to exit or stop the execution.

import java.util.Scanner;

public class CodesCracker
{
   public static void main(String[] args)
   {
      float a, b, res=0;
      int choice;
      Scanner scan = new Scanner(System.in);
      
      while(true)
      {
         System.out.println("1. Addition");
         System.out.println("2. Subtraction");
         System.out.println("3. Multiplication");
         System.out.println("4. Division");
         System.out.println("5. Exit");
         System.out.print("Enter Your Choice (1-5): ");
         choice = scan.nextInt();
         
         switch(choice)
         {
            case 1:
               System.out.print("\nEnter any Two Number: ");
               a = scan.nextFloat();
               b = scan.nextFloat();
               res = a+b;
               break;
            case 2:
               System.out.print("\nEnter any Two Number: ");
               a = scan.nextFloat();
               b = scan.nextFloat();
               res = a-b;
               break;
            case 3:
               System.out.print("\nEnter any Two Number: ");
               a = scan.nextFloat();
               b = scan.nextFloat();
               res = a*b;
               break;
            case 4:
               System.out.print("\nEnter any Two Number: ");
               a = scan.nextFloat();
               b = scan.nextFloat();
               res = a/b;
               break;
            case 5:
               return;
            default:
               System.out.println("\nInvalid choice!");
               break;
         }
         System.out.println("\nResult = " +res+ "\n");
      }
   } 
}

Here is its sample run with some user inputs to perform the calculation:

simple calculator program in java using switch

Calculator Program in Java using Functions and switch

This program is created using user-defined functions. This program works exactly same as of previous program.

import java.util.Scanner;

public class CodesCracker
{
   public static void main(String[] args)
   {
      float a, b, res=0;
      int choice;
      Scanner scan = new Scanner(System.in);
      
      while(true)
      {
         init();
         choice = scan.nextInt();
         
         switch(choice)
         {
            case 1:
               msg();
               a = scan.nextFloat();
               b = scan.nextFloat();
               res = add(a, b);
               break;
            case 2:
               msg();
               a = scan.nextFloat();
               b = scan.nextFloat();
               res = sub(a, b);
               break;
            case 3:
               msg();
               a = scan.nextFloat();
               b = scan.nextFloat();
               res = mul(a, b);
               break;
            case 4:
               msg();
               a = scan.nextFloat();
               b = scan.nextFloat();
               res = div(a, b);
               break;
            case 5:
               return;
            default:
               System.out.println("\nInvalid choice!");
               break;
         }
         System.out.println("\nResult = " +res+ "\n");
      }
   } 
   public static void init()
   {
      System.out.println("1. Addition");
      System.out.println("2. Subtraction");
      System.out.println("3. Multiplication");
      System.out.println("4. Division");
      System.out.println("5. Exit");
      System.out.print("Enter Your Choice (1-5): ");
   }
   public static void msg()
   {
      System.out.print("\nEnter any Two Number: ");
   }
   public static float add(float x, float y)
   {
      return x+y;
   }
   public static float sub(float x, float y)
   {
      return x-y;
   }
   public static float mul(float x, float y)
   {
      return x*y;
   }
   public static float div(float x, float y)
   {
      return x/y;
   }
}

This program produces same output as of previous program.

Same Program in Other Languages

Java Online Test


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