#include <stdio.h>

// There is no need to allocate the third position for temp
void reverse_array(int a[], int cnt)
{
	int first, last;
	for (first=0, last=cnt-1; first<last; first++, last--)
	{
		inplace_swap(&a[first], &a[last]);
	}
}

int main()
{
	int a[5] = {1,2,3,4,5};
	reverse_array(a, 5);
	for (int i=0; i<5; i++)
	{
		printf("%d ", a[i]);
	}
	printf("\n");
	return 0;
}
 

這裡的交換資料採用了布林代數中的布林環，如果採用

void inplace_swap(int *x, int *y)
{
	int itmp = *x;
	*x =  *y;
	*y = itmp;
}

void inplace_swap(int *x, int *y)
{
	int *ptmp = x;
	x =  y;
	y = ptmp;
}