Java Program to Multiply Two Numbers

How to multiply in java – Java Program to Multiply Two Numbers

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How to multiply in java: In the previous article, we have seen Java Program to Subtract Two Numbers

In this article we are going to see how to multiply two numbers using Java Programming language.

Java Program to Multiply Two Numbers

Before jumping to the program directly let’s know what is Multiplication.

Explanation:

Multiplication is one of mathematical operation where we find the product of two or more numbers. In general to add equal groups. It is represented by the symbol *.

Example:

15*2=30

10*12=120

2500*2=5000

Let’s see different ways to multiply two numbers.

Method-1: Java Program to Multiply Two Numbers By Using Multiplication ‘*’ Operator

Approach:

  1. Create scanner class object.
  2. Take user input for two numbers.
  3. Find the result using ‘*‘ operator.

Program:

import java.util.Scanner;

public class Main 
{
    public static void main(String[] args) 
    {
        //Scanner class object created
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter two numbers: ");
        //Taking two numbers input from user 
        int a = sc.nextInt();
        int b = sc.nextInt();
        //Multiplying two numbers using arthmetic operator * and printing result
        System.out.println("The multiplication of " + a + " and " + b + " is " + (a * b));
    }
}


Output:

Enter two numbers: 
100
6
The multiplication of 100 and 6 is 600

Method-2: Java Program to Multiply Two Numbers By Using for Loop and Addition + Operator

Approach:

  1. Create scanner class object.
  2. Take user input for two numbers a and b.
  3. Declare an integer variable mul and initialize it to 0.
  4. Run a for loop from 0 till b.
  5. Add a to mul inside the loop.
  6. Print mul.

Program:

import java.util.Scanner;

public class Main 
{
    public static void main(String[] args) 
    {
        //Scanner class object created
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter two numbers: ");
        //Taking input of two numbers
        int a = sc.nextInt();
        int b = sc.nextInt();
        //declaring an integer variable 'mul' to hold multiplication value
        //and initially assigning it value as 0
        int mul = 0;
        
        //Multiplying two numbers
        //By using for loop and addition operator
        for (int i = 0; i < b; i++) 
        {
            mul += a;
        }
        System.out.println("The multiplication of " + a + " and " + b + " is " + mul);
    }
}


Output:

Enter two numbers: 
5
20
The multiplication of 5 and 20 is 100

Method-3: Java Program to Multiply Two Numbers By Using Recursion

Approach:

  1. Create scanner class object.
  2. Declare two integer variables a and b  and take user input for two numbers.
  3. Use the recursive function.
  4. If any one of the two nums is zero return 0.
  5. If b is negative call the method by negating b and returning negative of the returned positive value.
  6. If b is positive recursively call the method by reducing by 1 until b becomes 0 and return its addition with a.

Program:

import java.util.Scanner;

public class Main 
{
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter two numbers: ");
        int a = sc.nextInt();
        int b = sc.nextInt();
        //calling multiply_two_nums() method
        System.out.println("The multiplication of " + a + " and " + b + " is " + multiply_two_nums(a, b));
    }
    
    //multiply_two_nums() user defined method
    public static int multiply_two_nums(int a, int b) 
    {

        /* 0 multiplied with anything gives 0 */
        if (b == 0 || a == 0)
            return 0;

        // recursively call the method until b becomes 0
        if (b > 0)
            return (a + multiply_two_nums(a, b - 1));

        if (b < 0)
            return -multiply_two_nums(a, -b);

        return -1;
    }
}


Output:

Case-1
Enter two numbers: 
4
5
The multiplication of 4 and 5 is 20

Case-2
Enter two numbers: 
10
-12
The multiplication of 10 and -12 is -120

Case-3
Enter two numbers: 
50
0
The multiplication of 50 and 0 is 0

Practice Java programming from home without using any fancy software just by tapping on this Simple Java Programs for Beginners tutorial.

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