简单的C51函数指针程序

/*___希望对初学的朋友有一点帮助___*/

#include<reg52.h>
#define uint unsigned int

void delay(uint t)
{
   while(t--);
}

uint sum(uint a,uint b)
 {
    uint c=a|b;
    return c;
 }

uint main()
 {
  uint (*p)(uint x,uint y);  //定义函数指针
     
  uint RET,REE,EER,ERR;    //定义存储变量
 
  p=sum;          //函数指针指向
  
  RET=(*p)(0x00,0xaa);     //函数指针赋值
  REE=(*p)(0x00,0x55); 
  EER=(*p)(0x00,0xff); 
  ERR=(*p)(0x00,0x00);
  
     while(1)
     {
       P2=RET; delay(40000); //赋给P2显示
       P2=REE; delay(40000);
       P2=RET; delay(40000);
       P2=REE; delay(40000);
      
       P2=EER; delay(40000);
       P2=ERR; delay(40000);
       P2=EER; delay(40000);
       P2=ERR; delay(40000);
    }
   return 0;
 }