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Introduction

Print an Integer (Entered by the User)Add Two Integers Multiply two Floating Point Numbers Find ASCII value of a character Compute Quotient and Remainder Swap Two Numbers Check Whether a Number is Even or Odd Find the Frequency of Character in a String Remove All Whitespaces from a String Round a Number to n Decimal Places

Decision Making and Loop

Check Whether an Alphabet is Vowel or Consonant Find the Largest Among Three Numbers Find all Roots of a Quadratic Equation Check Leap Year Check Whether a Number is Positive or Negative Check Whether a Character is Alphabet or Not Calculate the Sum of Natural Numbers Find Factorial of a Number Generate Multiplication Table Display Fibonacci Series Find GCD of two Numbers Find LCM of two Numbers Display Characters from A to Z using loop Count Number of Digits in an Integer Reverse a Number Calculate the Power of a Number Check Whether a Number is Palindrome or Not Check Whether a Number is Prime or Not Display Prime Numbers Between Two Intervals Check Armstrong Number Display Armstrong Number Between Two Intervals Display Factors of a Number Make a Simple Calculator Using switch...case Count the Number of Vowels and Consonants in a Sentence Sort Elements in Lexicographical Order (Dictionary Order)Create Pyramid and Pattern

Functions

Display Prime Numbers Between Intervals Using Function Display Armstrong Numbers Between Intervals Using Function Check Whether a Number can be Expressed as Sum of Two Prime Numbers Find the Sum of Natural Numbers using Recursion Find Factorial of a Number Using Recursion Find G.C.D Using Recursion Convert Binary Number to Decimal and vice-versa Convert Octal Number to Decimal and vice-versa Convert Binary Number to Octal and vice-versa Reverse a Sentence Using Recursion calculate the power using recursion

Arrays

Calculate Average Using Arrays Find Largest Element in an Array Calculate Standard Deviation Add Two Matrix Using Multi-dimensional Arrays Multiply to Matrix Using Multi-dimensional Arrays Multiply two Matrices by Passing Matrix to a Function Find Transpose of a Matrix Print an Array Concatenate Two Arrays Convert Character to String and Vice-Versa Check if An Array Contains a Given Value

Collections

Join Two Lists Convert List (ArrayList) to Array and Vice-Versa Convert Map (HashMap) to List Convert Array to Set (HashSet) and Vice-Versa Sort a Map By Values

Object and Class

Add Two Complex Numbers by Passing Class to a Function Calculate Difference Between Two Time Periods

Advanced

Convert String to Date Get Current Date/TIme Convert Milliseconds to Minutes and Seconds Add Two Dates Get Current Working Directory Convert Byte Array to Hexadecimal Create String from Contents of a File Append Text to an Existing File Convert a Stack Trace to a String Convert File to byte array and Vice-Versa Convert InputStream to String Convert OutputStream to String Lookup enum by String value Compare Strings Sort ArrayList of Custom Objects By Property Check if a String is Numeric

Java Program to Multiply Two Matrix Using Multi-dimensional Arrays

To understand this example, you should have the knowledge of the following Java programming topics:

For matrix multiplication to take place, the number of columns of first matrix must be equal to the number of rows of second matrix. In our example, i.e.


              
c1 = r2

Also, the final product matrix is of size r1 x c2, i.e.


              
product[r1][c2]

You can also multiply two matrices using functions.

Example: Program to Multiply Two Matrices


              
public class MultiplyMatrices {

    public static void main(String[] args) {
        int r1 = 2, c1 = 3;
        int r2 = 3, c2 = 2;
        int[][] firstMatrix = { {3, -2, 5}, {3, 0, 4} };
        int[][] secondMatrix = { {2, 3}, {-9, 0}, {0, 4} };

        // Mutliplying Two matrices
        int[][] product = new int[r1][c2];
        for(int i = 0; i < r1; i++) {
            for (int j = 0; j < c2; j++) {
                for (int k = 0; k < c1; k++) {
                    product[i][j] += firstMatrix[i][k] * secondMatrix[k][j];
                }
            }
        }

        // Displaying the result
        System.out.println("Multiplication of two matrices is: ");
        for(int[] row : product) {
            for (int column : row) {
                System.out.print(column + "    ");
            }
            System.out.println();
        }
    }
}

Output


              
Multiplication of two matrices is:
24    29
6    25

In the above program, the multiplication takes place as:


              
|-    (a11 x b11) + (a12 x b21) + (a13 x b31)    (a11 x b12) + (a12 x b22) + (a13 x b32)    -|
|_    (a21 x b11) + (a22 x b21) + (a23 x b31)    (a21 x b12) + (a22 x b22) + (a23 x b32)    _|

In our example, it takes place as:


              
|-    (3 x 2) + (-2 x -9) + (5 x 0) = 24    (3 x 3) + (-2 x 0) + (5 x 4) = 29    -|
|_    (3 x 2) + ( 0 x -9) + (4 x 0) = 6    (3 x 3) + ( 0 x 0) + (4 x 4) = 25    _|

Also Read:

Java Program to Add Two Matrix Using Multi-dimensional Arrays