Write a java program to multiply two matrices and output the resultant matrix.
Example:
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Input: //Matrix 1 1 2 3 1 1 1 //Matrix 2 1 2 1 3 1 1 Output: //Resultant matrix 6 11 3 6 |
Before the starting the process of matrix multiplication first we need to check the order of the two given matrix, whether they can be multiplied or not because two matrices A and B can only be multiplied if the number of columns in A is equal to the number of rows in B.
Also, the order of the resultant matrix is:
- row = number of rows in A
- col = number of columns in B
If all is well, then we need to multiply matrices as done in standard mathematical matrix multiplication.
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import java.util.Scanner; //Matrix class class Matrix{ int row, col; int elements[][]; Matrix(int row, int col){ this.row = row; this.col = col; elements = new int[row][col]; } //to dusplay the matrix public void display(){ for(int i=0; i<row; i++){ for(int j=0; j<col; j++){ System.out.print(elements[i][j]+"\t"); } System.out.println(); } } } class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); //Input order of 1st matrix System.out.println("Enter order of Matrix 1"); Matrix matrix1 = new Matrix(in.nextInt(),in.nextInt()); //input order of 2nd matrix System.out.println("Enter order of Matrix 2"); Matrix matrix2 = new Matrix(in.nextInt(),in.nextInt()); //check if multiplication is possible if(matrix1.col != matrix2.row){ System.out.println("Matrix multiplication not possible with given order"); //If no then terminate the program System.exit(0); } int i=0, j=0, sum=0, k=0; //Input elements in 1st matrix System.out.println("Enter elements of Matrix 1"); for(i=0; i<matrix1.row; i++){ for(j=0; j<matrix1.col; j++){ matrix1.elements[i][j] = in.nextInt(); } } //input elements in 2nd matrix System.out.println("Enter elements of Matrix 2"); for(i=0; i<matrix2.row; i++){ for(j=0; j<matrix2.col; j++){ matrix2.elements[i][j] = in.nextInt(); } } //Declare resultant matrix with order of 1st.row x 2nd.col Matrix result = new Matrix(matrix1.row, matrix2.col); //Matrix multiplication algorithm for(i=0; i<result.row; i++){ for(j=0; j<result.col; j++){ sum=0; for(k=0; k<matrix1.col; k++){ sum += matrix1.elements[i][k]*matrix2.elements[k][j]; } result.elements[i][j] = sum; } } //Display result System.out.println("Resultant Matrix"); result.display(); } } |
Output
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Enter order of Matrix 1 2 3 Enter order of Matrix 2 3 2 Enter elements of Matrix 1 1 2 3 1 1 1 Enter elements of Matrix 2 1 2 1 3 1 1 Resultant Matrix 6 11 3 6 ------------------------- Enter order of Matrix 1 3 4 Enter order of Matrix 2 2 3 Matrix multiplication not possible with given order |
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