4*4键盘扫描C程序

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4*4键盘扫描C程序

#include<reg52.h>
#define uchar unsigned char
uchar code table[]={0xC0,0xF9,0xA4,0xB0,0x99,
    0x92,0x82,0xF8,0x80,0x90,
    0x88,0x83,0xC6,0xA1,0x86,0x8E};
uchar temp,num;
void display(uchar);
void delay(uchar a)
{
uchar b;
for(;a>0;a--)
    for(b=200;b>0;b--);
}
void main()
{
while(1)
{
    P2=0x7f;
temp=P2;
temp&=0x0f;
if(temp!=0x0f)
    {
delay(50);
if(temp!=0x0f)
{
   switch(temp)
   {
     case 0x07: num="0"; break;
     case 0x0b: num="1"; break;
case 0x0d: num="2"; break;
     case 0x0e: num="3"; break;
       }
}
}
P2=0xbf;
temp=P2;
temp&=0x0f;
if(temp!=0x0f)
{
delay(50);
if(temp!=0x0f)
{
   switch(temp)
   {
     case 0x07: num="4"; break;
     case 0x0b: num="5"; break;
     case 0x0d: num="6"; break;
     case 0x0e: num="7"; break;
       }
    }
}
P2=0xdf;
temp=P2;
temp&=0x0f;
if(temp!=0x0f)
{
delay(50);
if(temp!=0x0f)
{
   switch(temp)
   {
     case 0x07: num="8"; break;
     case 0x0b: num="9"; break;
     case 0x0d: num="10"; break;
     case 0x0e: num="11"; break;
       }
    }
}
P2=0xef;
temp=P2;
temp&=0x0f;
if(temp!=0x0f)
{
delay(50);
if(temp!=0x0f)
{
   switch(temp)
   {
     case 0x07: num="12"; break;
     case 0x0b: num="13"; break;
case 0x0d: num="14"; break;
     case 0x0e: num="15"; break;
       }
}
}
display(num);
}
}
void display(uchar i)
{
P3=0xf0;
P0=table[i];
}