Matrix multiplication in C language: C program to multiply matrices (two dimensional array), this program multiplies two matrices which will be entered by the user. Firstly user will enter the order of a matrix. If the entered orders of two matrix is such that they can't be multiplied then an error message is displayed on the screen. You have already studied the logic to multiply them in Mathematics.

## Matrix multiplication in C language

#include <stdio.h> int main() { int m, n, p, q, c, d, k, sum = 0; int first[10][10], second[10][10], multiply[10][10]; printf("Enter the number of rows and columns of first matrix\n"); scanf("%d%d", &m, &n); printf("Enter the elements of first matrix\n"); for (c = 0; c < m; c++) for (d = 0; d < n; d++) scanf("%d", &first[c][d]); printf("Enter the number of rows and columns of second matrix\n"); scanf("%d%d", &p, &q); if (n != p) printf("Matrices with entered orders can't be multiplied with each other.\n"); else { printf("Enter the elements of second matrix\n"); for (c = 0; c < p; c++) for (d = 0; d < q; d++) scanf("%d", &second[c][d]); for (c = 0; c < m; c++) { for (d = 0; d < q; d++) { for (k = 0; k < p; k++) { sum = sum + first[c][k]*second[k][d]; } multiply[c][d] = sum; sum = 0; } } printf("Product of entered matrices:-\n"); for (c = 0; c < m; c++) { for (d = 0; d < q; d++) printf("%d\t", multiply[c][d]); printf("\n"); } } return 0; }

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An output of 3 X 3 matrix multiplication C program is shown as example below.

Matrices are frequently used while doing programming and are used to represent graph data structure, in solving system of linear equations and many more. Lot of research is being done on how to multiply matrices using minimum number of operations. You can also implement it using pointers.