rare matrix

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

#define NMAX 1000
typedef struct {
    int rows, cols, len;
    int row[NMAX], col[NMAX];
    double val[NMAX];
} RareMatrix;

static void readRareMatrix(RareMatrix* m) {
    assert(scanf_s("%d%d%d", &m->rows, &m->cols, &m->len));
    for (int i = 0; i < m->len; i++) {
        assert(scanf_s("%d%d%lf", &m->row[i], &m->col[i], &m->val[i]));
    }
}

static void printRareMatrix(const RareMatrix* const rMat) {
    for (int i = 0; i < rMat->rows; i++) {
        for (int j = 0; j < rMat->cols; j++) {
            double val = .0;
            for (int k = 0; k < rMat->len; k++) {
                if (rMat->row[k] == i && rMat->col[k] == j) {
                    val = rMat->val[k];
                    break;
                }
            }
            printf("%lf ", val);
        }
        printf("\n");
    }
}

static void addRareMats(const RareMatrix* const rMat1, const RareMatrix* const rMat2, RareMatrix* rMat3) {
    rMat3->rows = rMat1->rows;
    rMat3->cols = rMat1->cols;
    rMat3->len = 0;
    for (int i = 0; i < rMat1->len; i++) {
        rMat3->row[rMat3->len] = rMat1->row[i];
        rMat3->col[rMat3->len] = rMat1->col[i];
        rMat3->val[rMat3->len] = rMat1->val[i];
        rMat3->len++;
    }
    for (int i = 0; i < rMat2->len; i++) {
        int j;
        for (j = 0; j < rMat3->len; j++) {
            if (rMat3->row[j] == rMat2->row[i] && rMat3->col[j] == rMat2->col[i]) {
                rMat3->val[j] += rMat2->val[i];
                break;
            }
        }
        if (j == rMat3->len) {
            rMat3->row[rMat3->len] = rMat2->row[i];
            rMat3->col[rMat3->len] = rMat2->col[i];
            rMat3->val[rMat3->len] = rMat2->val[i];
            rMat3->len++;
        }
    }
}

int main() {
    RareMatrix rMat1, rMat2, rMat3;
    readRareMatrix(&rMat1);
    readRareMatrix(&rMat2);
    addRareMats(&rMat1, &rMat2, &rMat3);
    printRareMatrix(&rMat3);
    return 0;
}