cs12-2.c

《手把手教你学单片机的C程序设计》及实验程序

#include <REG51.H>		
#define uchar unsigned char
#define uint unsigned int	
uchar code SEG7[10]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};
//**************************************
void delay(uint k)			
{						
uint i,j;					
for(i=0;i<k;i++){			
for(j=0;j<121;j++)				
{;}}						
}							
//*************************************
void main(void)				
{						
uchar a=3,b=1,c=9;
uchar temp;			
	//***********************************
	if((c>b)&&(c>a))
	{temp=c;
	c=a;a=temp;}
	else if((b>a)&&(b>c))
	{temp=b;
	b=a;a=temp;}
	//===============================
	if(c>b)
	{temp=c;
	c=b;b=temp;}
	//===============================
		while(1)
		{P0=SEG7[a];
		P2=0xfb;			
 		delay(1);
		P0=SEG7[b];
		P2=0xfd;			
 		delay(1);	
		P0=SEG7[c];
		P2=0xfe;			
 		delay(1);
		}
}