51单片机矩阵按键数码管显示 超简洁程序

#include 
#define uchar unsigned char
#define uint unsigned int
//宏定义
sbit P20= P2^0;
//端口位定义
//数码管段码定义

uchar SMG_CODE[] = {0x40,0x79,0x24,0x30,0x19,0x12,0x02,0x78,0x00,0x10,0x88,0x83,0xC6,0xa1,0x86,0x8E,0xff};
uchar key_code = 16;
void delay()
			{

      int i;

      for(i = 8; i< 120; i++);
			}

//数码管显示数字初值为16是刚开始的显示全灭
 //键盘扫描函数

uchar key_scan()
{
      uchar key = 0,i,cr[2] =0,j= 0;

      P3 = 0x0F;  //P3口列值输入初始化if(P3 ?- 8XOF)  1/判断有没有键按下

if(P3!=0X0f)
{
	 delay();    
		if(P3 != 0X0F)
		{
				key = P3;
				P3 = 0XF0;
				key=key | P3;
				while(P3 != 0xf0);
				for(i=0;i<8;i++)
				{
				key=key>>1;
					if(!CY)
					{
					cr[j++]=i ;
					}
				}
					key_code =cr[0]+(cr[1]- 4)*4;//计算键值对应的数字

		}
}
return key_code;
}
//返回键值对应的数字

void main()
{
	P20= 0;
while(1)
{
		P0=SMG_CODE[key_scan()];
}

//调用键盘扫描函数并输出对应的数字
}