大哥幫我看看LED程序問題

這個程序哪兒錯了？？？？？

#include<reg51.h>
int delay(void)
{
 unsigned int i,j;
  
   for(i=0;i<500;i++)
    {
   for(j=0;j<1200;j++)
     {;}
  }
  }
  sheng(void)
 {
   P0=0xaa;
   }
 void ai(void)
  {
   P0=0x55;
   }
 void main(void)
 {
   while(1)
     {
    sheng();
    delay();
    ai();
    delay();
  }
  }
錯誤顯示

SHENGAIJUN.C(27): error C100: unprintable character 0xA1 skipped

SHENGAIJUN.C(27): error C100: unprintable character 0xBB skipped

SHENGAIJUN.C(27): error C100: unprintable character 0xA1 skipped

SHENGAIJUN.C(27): error C100: unprintable character 0xBB skipped