matrix_multiply_iterative.c

/**********************************************************************************
Name:           Dhruba Saha
Roll No:        B.Sc(Sem-IV)-04
Program No:     3
Program Name:   Write a C program to multiply two matrices by iterative
approach. Date:           05/05/2022
***********************************************************************************/

#include <stdio.h>
#include <stdlib.h>

int **allocMem();
int inputMat();
int multiplyMat();
void outputMat();

void main() {
  int m, n, **a, **b, **c;

  printf("Enter the number of rows and columns of matrices:\n");
  scanf("%d%d", &m, &n);

  a = allocMem(m, n);
  b = allocMem(m, n);
  c = allocMem(m, n);

  printf("Enter the elements of first matrix:\n");
  inputMat(a, m, n);

  printf("Enter the elements of second matrix:\n");
  inputMat(b, m, n);

  printf("Matrix A:\n");
  outputMat(a, m, n);

  printf("Matrix B:\n");
  outputMat(b, m, n);

  multiplyMat(a, b, c, m, n);

  printf("The product of the two matrices:\n");
  outputMat(c, m, n);

  free(a);
  free(b);
  free(c);
}

int **allocMem(int m, int n) {
  int **x, i;
  x = (int **)calloc(m, sizeof(int *));
  for (i = 0; i < m; i++) {
    x[i] = (int *)calloc(n, sizeof(int));
  }
  return x;
}

int inputMat(int **a, int m, int n) {
  int i, j;
  for (i = 0; i < m; i++) {
    for (j = 0; j < n; j++) {
      printf("Element %d, %d:\n", i + 1, j + 1);
      scanf("%d", &a[i][j]);
    }
  }
}

int multiplyMat(int **a, int **b, int **c, int m, int n) {
  int i, j, k;
  for (i = 0; i < m; i++) {
    for (j = 0; j < n; j++) {
      c[i][j] = 0;
      for (k = 0; k < n; k++) {
        c[i][j] += a[i][k] * b[k][j];
      }
    }
  }
}

void outputMat(int **a, int m, int n) {
  int i, j;
  for (i = 0; i < m; i++) {
    for (j = 0; j < n; j++) {
      printf("%d ", a[i][j]);
    }
    printf("\n");
  }
}

/*
Enter the number of rows and columns of matrices:
2
2
Enter the elements of first matrix:
Element 1, 1:
2
Element 1, 2:
2
Element 2, 1:
2
Element 2, 2:
2
Enter the elements of second matrix:
Element 1, 1:
2
Element 1, 2:
2
Element 2, 1:
2
Element 2, 2:
2
Matrix A:
2 2
2 2
Matrix B:
2 2
2 2
The product of the two matrices:
8 8
8 8
*/