这段单片机代码按第一个按键时显示在第1位,按第2个按键时显示在了第2位,如何一起显示 -

#include <reg51.h>
#define uint unsigned int
#define uchar unsigned char
uchar code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x00};
uchar key=0;//键值变量
void delayms(uint k)
{
uint i,j;
for(i=k;i>0;i--)
for(j=115;j>0;j--);
}
void key_scan() //按键扫描程序
{
static bit sign=0; //按键自锁标志
static uint count=0; //消抖计数变量
uchar num=0; //临时变量
P3=0xf0; //赋值P3 1111 0000
if(P3!=0xf0) //检测有按键按下
{
count++; //消抖计数
if((count>=20)&&(sign==0)) //100~1000，根据主循环周期调整约10~20ms
{
sign=1; //按键自锁标志置1
num=P3; //保存P3值xxxx 0000，x为0或1
num|=0x0f; //保存num按位或0x0f值xxxx 1111
P3=num; //赋值P3 xxxx 1111
num=P3; //保存P3值xxxx xxxx
switch(num)
{
case 0xee: key= 1; break;
case 0xde: key= 2; break;
case 0xbe: key= 3; break;
case 0x7e: key= 4; break;
case 0xed: key= 5; break;
case 0xdd: key= 6; break;
case 0xbd: key= 7; break;
case 0x7d: key= 8; break;
case 0xeb: key= 9; break;
case 0xdb: key=10; break;
case 0xbb: key=11; break;
case 0x7b: key=12; break;
case 0xe7: key=13; break;
case 0xd7: key=14; break;
case 0xb7: key=15; break;
case 0x77: key=16; break;
}
}
}
else //键抬起
{
sign=0; //按键自锁标志清0
count=0; //消抖计数清0
}
}
void display() //数码管显示程序
{
static uchar a[6]={10,10,10,10,10,10};
static uchar i,j;
if (key==1)a[0]=key;
else if(key==2)a[1]=key;
else if(key==3)a[2]=key;
else if(key==4)a[3]=key;
else if(key==5)a[4]=key;
else if(key==6)a[5]=key;
else if(key==7)//清除
{
for(j=0;j<6;j++)
a[j]=10;
}
P0=0x00;
P2=~(0x01<<i);
P0=table[a[i]];
i=++i%6;
}
void main() //主函数
{
while(1)
{
key_scan(); //按键扫描程序
display(); //数码管显示键值1~16
delayms(1); //延时控制主循环周期约1ms
}
}

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