lab10.c

/* example10-3.c */
#include <stdlib.h>
#include <stdio.h>

/* https://www.eskimo.com/~scs/cclass/int/sx9b.html */

void print_matrix(float **M, int n, int m) {
    int i,j;
    for (i=0; i<n; i++)
	{
		for (j=0; j<m; j++)
		{
			printf(" %10.3f",M[i][j]);
		}
		printf("\n");
	}
}

float** calloc_matrix(n, m) {
    float **M = malloc(n * sizeof(float *));

	if(M == NULL) return EXIT_FAILURE;

	int i,j;
	for (i=0; i<n; i++)
	{
	    M[i] = calloc(m, sizeof(int));
	    if(M[i] == NULL) return EXIT_FAILURE;
	}
	return M;
}

void copy_to(float **A, float **B, int n, int m) {
    int i,j;
	for (i=0; i<n; i++)
        for (j=0; j<m; j++)
			A[i][j] = B[i][j];
}

void add_to(float **A, float **B, int n, int m) {
    int i,j;
	for (i=0; i<n; i++)
        for (j=0; j<m; j++)
			A[i][j] += B[i][j];
}

void subtract_to(float **A, float **B, int n, int m) {
    int i,j;
	for (i=0; i<n; i++)
        for (j=0; j<m; j++)
			A[i][j] -= B[i][j];
}

int main()
{
	int n, m;
    printf("Enter matrix dim: ");
    scanf("%i %i", &n, &m);

	float **A = calloc_matrix(n, m);
	float **B = calloc_matrix(n, m);
	float **C = calloc_matrix(n, m);
	float **D = calloc_matrix(n, m);

	int i,j;
	for (i=0; i<n; i++)
	{
        for (j=0; j<m; j++)
		{
			printf("A[%d][%d]: ",i,j);
			scanf("%f",&A[i][j]);
		}
	}
	for (i=0; i<n; i++)
	{
        for (j=0; j<m; j++)
		{
			printf("B[%d][%d]: ",i,j);
			scanf("%f",&B[i][j]);
		}
	}

	copy_to(C, A, n, m);
	add_to(C, B, n, m);
	copy_to(D, A, n, m);
	subtract_to(D, B, n, m);

	printf("A:\n");
	print_matrix(A, n, m);
	printf("B:\n");
	print_matrix(B, n, m);
	printf("C:\n");
	print_matrix(C, n, m);
	printf("D:\n");
	print_matrix(D, n, m);

	return EXIT_SUCCESS;
}