PTA实验7-2-2 矩阵运算 (20point(s)) Easy only once

#include<stdlib.h>
#include<stdio.h>
#define maxn 11

int n;
int ma[maxn][maxn];

int main(){
    int a;
    scanf("%d",&n);
    int sum = 0;
    for (int i = 0; i < n; i++) {
        //int sum = 0;
        for (int j = 0; j < n; j++) {
            scanf("%d", &ma[i][j]);
            //sum += a;

        }
        //printf("%d\n", sum);
    }
    for (int i = 0; i < n-1; i++) {
        //不计入最后一行；
        for (int j = 0; j < n - 1; j++) {
            //不计入最后一列；
            if (i + j != n - 1) {
                //如果不是副对角线元素
                sum += ma[i][j];
            }
        }
    }
    printf("%d", sum);
}