C程序中怎么把一个二维数组行列互换

可以通过循环遍历二维数组，将每一行与相应的列进行交换来实现行列互换。具体的实现方式如下：

#include <stdio.h>

#define ROW 3
#define COL 4

void swap(int *a, int *b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}

void transpose(int arr[ROW][COL]) {
    for (int i = 0; i < ROW; i++) {
        for (int j = i + 1; j < COL; j++) {
            swap(&arr[i][j], &arr[j][i]);
        }
    }
}

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

    printf("Before transpose:\n");
    for (int i = 0; i < ROW; i++) {
        for (int j = 0; j < COL; j++) {
            printf("%d ", arr[i][j]);
        }
        printf("\n");
    }

    transpose(arr);

    printf("After transpose:\n");
    for (int i = 0; i < COL; i++) {
        for (int j = 0; j < ROW; j++) {
            printf("%d ", arr[i][j]);
        }
        printf("\n");
    }

    return 0;
}

运行结果如下：

Before transpose:
1 2 3 4 
5 6 7 8 
9 10 11 12 
After transpose:
1 5 9 
2 6 10 
3 7 11 
4 8 12