C语言二维数组顺时钟遍历

二维数组顺时针遍历可以使用模拟的方式，设置四个变量来控制遍历方向和位置。

以下是一个示例代码：

#include <stdio.h>

#define ROW 3
#define COL 4

void clockwise_traversal(int arr[][COL], int row, int col) {
    int left = 0, right = col - 1;
    int top = 0, bottom = row - 1;
    
    while (left <= right && top <= bottom) {
        // 从左往右
        for (int i = left; i <= right; i++) {
            printf("%d ", arr[top][i]);
        }
        top++;

        // 从上往下
        for (int i = top; i <= bottom; i++) {
            printf("%d ", arr[i][right]);
        }
        right--;

        // 从右往左
        if (top <= bottom) {
            for (int i = right; i >= left; i--) {
                printf("%d ", arr[bottom][i]);
            }
            bottom--;
        }

        // 从下往上
        if (left <= right) {
            for (int i = bottom; i >= top; i--) {
                printf("%d ", arr[i][left]);
            }
            left++;
        }
    }
}

int main() {
    int arr[ROW][COL] = {
        {1, 2, 3, 4},
        {5, 6, 7, 8},
        {9, 10, 11, 12},
    };

    clockwise_traversal(arr, ROW, COL);
    return 0;
}

输出结果为：

1 2 3 4 8 12 11 10 9 5 6 7