你的for循环嵌套有问题。我帮你写了一版实现,供你参考。如果有用望采纳。
#include <stdio.h>
#define N 5
int main() {
int m[N][N];
for (int i = 0; i < N; i++) {
for (int j = 0; j < N; j++) {
scanf("%d", &m[i][j]);
}
}
int prime = 0, secondary = 0;
for (int i = 0; i < N; i++) {
prime += m[i][i];
secondary += m[i][N - i - 1];
}
printf("%d %d\n", prime, secondary);
return 0;
}