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
");
  printf("a = %d
",a);
  printf("b = %d
",b);
  
  //Swap the number
  swap(&a,&b,int);
  
  
  printf("

Value of a and b After swaping
");
  printf("a = %d
",a);
  printf("b = %d
",b);
  
    return 0; 
}