如何在C中定义多行宏定义？

请参阅下面的示例，其中我将交换两个变量的值。 do-while（0）结构很不错

#include <stdio.h> 

#define swap(x,y,T) do { \
    T temp = (*x);\
    (*x) = (*y); \
    (*y) = temp; \
} while (0)

int main(void)
{
  int a = 5;
  int b = 9;

  printf("Value of a and b before swaping\n");
  printf("a = %d\n",a);
  printf("b = %d\n",b);

  //Swap the number
  swap(&a,&b,int);

  printf("\n\nValue of a and b After swaping\n");
  printf("a = %d\n",a);
  printf("b = %d\n",b);

    return 0;
}