参考程序：

#include <bits/stdc++.h>
using namespace std;const int MAXN = 105;
int a[MAXN][MAXN];int main() {int n;if (!(cin >> n)) return 0;for (int i = 0; i < n; ++i)for (int j = 0; j < n; ++j)cin >> a[i][j];int layers = n / 2; // 每次处理一圈，外层到里层共有 floor(n/2) 层// 对每一层做 (right-left) 次四元循环替换for (int layer = 0; layer < layers; ++layer) {int top = layer;int left = layer;int bottom = n - 1 - layer;int right = n - 1 - layer;// 对当前圈上的每一个偏移 i 做一次 4 格循环替换for (int i = 0; i < right - left; ++i) {int rTop = top,        cTop = left + i;int rRight = top + i,  cRight = right;int rBottom = bottom,  cBottom = right - i;int rLeft = bottom - i, cLeft = left;if (layer % 2 == 0) {// 顺时针 90° (CW)：左 -> 上, 下 -> 左, 右 -> 下, 上 -> 右int tmp = a[rLeft][cLeft];a[rLeft][cLeft]     = a[rBottom][cBottom];a[rBottom][cBottom] = a[rRight][cRight];a[rRight][cRight]   = a[rTop][cTop];a[rTop][cTop]       = tmp;} else {// 逆时针 90° (CCW)：上 -> 左, 右 -> 上, 下 -> 右, 左 -> 下int tmp = a[rTop][cTop];a[rTop][cTop]       = a[rRight][cRight];a[rRight][cRight]   = a[rBottom][cBottom];a[rBottom][cBottom] = a[rLeft][cLeft];a[rLeft][cLeft]     = tmp;}}}// 输出结果for (int i = 0; i < n; ++i) {for (int j = 0; j < n; ++j) {if (j) cout << ' ';cout << a[i][j];}cout << '\n';}return 0;
}