matrix_addition_multiplication.c

#include <stdio.h>
#define SIZE 50

struct mat {
    int row;
    int col;
    int value[SIZE][SIZE];
};

void scan_mat(struct mat *);
void print_mat(const struct mat *);
void add_mat(const struct mat *, const struct mat *, struct mat *);
void mul_mat(const struct mat *, const struct mat *, struct mat *);

int main(void) {
    struct mat m1, m2, result;
    char op;
    scan_mat(&m1);
    scanf(" %c", &op);
    scan_mat(&m2);
    switch (op) {
        case '+':
            add_mat(&m1, &m2, &result);
            break;
        case '*':
            mul_mat(&m1, &m2, &result);
            break;
    }
    print_mat(&result);
    return 0;
}

void scan_mat(struct mat *m_p) {
    scanf("%d %d", &(*m_p).row, &m_p->col);
    for (int i = 0; i < m_p->row; ++i)
        for (int j = 0; j < m_p->col; ++j)
            scanf("%d", &m_p->value[i][j]);
}

void print_mat(const struct mat *m_p){
    for (int i = 0; i < m_p->row; ++i) {
        for (int j = 0; j < m_p->col; ++j) {
            printf("%d ", m_p->value[i][j]);
            if (j == m_p->col - 1)
                printf("\n");
        }
    }
}

void add_mat(const struct mat *m1_p, const struct mat *m2_p, struct mat *result_p) { // matrix addition
    result_p->col=m1_p->col;
    result_p->row=m1_p->row;
    for(int i=0;i<result_p->row;++i){
        for(int j=0;j<result_p->col;++j){
            result_p->value[i][j]=m1_p->value[i][j]+m2_p->value[i][j];
        }
    }
}

void mul_mat(const struct mat *m1_p, const struct mat *m2_p, struct mat *result_p) { // matrix multiplication
    result_p->row=m1_p->row;
    result_p->col=m2_p->col;
    int value;
    for(int i=0;i<result_p->row;++i){
        for(int j=0;j<result_p->col;++j){
            result_p->value[i][j]=0;
            for(int k=0;k<m1_p->col;++k){
                result_p->value[i][j]+=m1_p->value[i][k]*m2_p->value[k][j];
            }

        }
    }
}