c语言二维数组的实验思路短了

供参考：

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N  5
#define M  6
int main()
{
    int a[N][M], i, j, sum = 0, max, max_r, max_c;
    srand((unsigned int)time(NULL));
    for (i = 0; i < N; i++){
        for (j = 0; j < M; j++){
            a[i][j] = rand() % 100;
            printf("%4d", a[i][j]);
        }
        printf("\n");
    }

    max = a[0][0]; max_r = 0; max_c = 0;
    for (i = 0; i < N; i++) {
        for (j = 0; j < M; j++) {
            if (i == 0 || j == 0 || i == N - 1 || j == M - 1) {//周边元素之和
                sum += a[i][j];
            }
            if (max < a[i][j]) {//最大值及下标
                max = a[i][j];
                max_r = i;
                max_c = j;
            }
        }
    }
    printf("周边元素之和：%d ,最大值：a[%d][%d]=%d", sum, max_r, max_c, a[max_r][max_c]);
    return 0;
}