写一个函数，使给定的一个二维数组（NXM）转置，即行列互换

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<string.h>
#include<Windows.h>

#define N 3
#define M 3
void rankexchange(int a1
[M])
{
int b1
[M];
for (int i = 0; i < N;i++)
for (int j = 0; j < M; j++)
{
b1[j][i] = a1[i][j];
}
for (int i = 0; i < N; i++)
for (int j = 0; j < M; j++)
{
a1[i][j] = b1[i][j];
}

}
void main()
{
int a
[M] = {
{ 1, 2, 3 },
{ 1, 2, 3 },
{ 1, 2, 3 }
};
rankexchange(a);
for (int i = 0; i < N; i++)//打印结果
{
for (int j = 0; j < M; j++)
{
printf("%3d", a[i][j]);
}
printf("\n");
}
system("pause");
}