# 51单片机计算器 使用数码管显示
比较简短的一种实现加减乘除计算功能的计算器，基于51单片机，使用数码管显示
> 本人有点强迫症，为了好看，把代码改成100行了哈哈
> 若是有不理解的地方，欢迎给我发邮箱 1836601275@qq.com
下面附上源码：
```c
#include <REGX52.H> //程序核心：始终显示num，操作改变num
void display(int num1); //显示函数
void DelayXms(unsigned int x); //延时函数
void keyScan(); //按键扫描
void keyAdd(); //数字多位输入
void pd(); //判断
int n1, n2, n3, n4, numKey=10000, num=0, num0=0;//显示的个十百千位 键值，显示值，存储值1
char fuhao='0',fuhao0='0'; //键入的符号值,存储的符号值
unsigned char duan[10]={0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};
void main(){
while(1){
keyScan(); //扫描键值
pd(); //判断键值情况
display(num); //显示函数
}
}
void keyAdd(){
if(numKey<10000){
num=num*10+numKey;
numKey=10000;
}
}
void pd(){
keyAdd(); //判断为数字，则为数字输入
if(fuhao=='c'){ //清零
num=0;
num0=0;
fuhao0='0';
fuhao='0';
}
if(fuhao=='+'){ //加法
fuhao0='+'; //将符号'+'存到变量fuhao0
fuhao='0'; //符号清零
num0=num; //将加数0存到变量num0
num=0;
}
if(fuhao=='-'){ //减法
fuhao0='-';
fuhao='0';
num0=num;
num=0;
}
if(fuhao=='*'){ //乘法
fuhao0='*';
fuhao='0';
num0=num;
num=0;
}
if(fuhao=='/'){ //除法
fuhao0='/';
fuhao='0';
num0=num;
num=0;
}
if(fuhao=='='){ //检测到符号为等号，则进行运算
if(fuhao0=='+')num=num0+num;
else if(fuhao0=='-')num=num0-num;
else if(fuhao0=='*')num=num0*num;
else if(fuhao0=='/')num=num0/num;
fuhao='0';
num0=0;
}
}
void keyScan(){
P3=0xef;//1110 1111
if(!P3_3){numKey=7;while(!P3_3);}if(!P3_2){numKey=8;while(!P3_2);}if(!P3_1){numKey=9;while(!P3_1);}if(!P3_0){fuhao='+';while(!P3_0);}
P3=0xdf;
if(!P3_3){numKey=4;while(!P3_3);}if(!P3_2){numKey=5;while(!P3_2);}if(!P3_1){numKey=6;while(!P3_1);}if(!P3_0){fuhao='-';while(!P3_0);}
P3=0xbf;
if(!P3_3){numKey=1;while(!P3_3);}if(!P3_2){numKey=2;while(!P3_2);}if(!P3_1){numKey=3;while(!P3_1);}if(!P3_0){fuhao='*';while(!P3_0);}
P3=0x7f;
if(!P3_3){fuhao='c';while(!P3_3);}if(!P3_2){numKey=0;while(!P3_2);}if(!P3_1){fuhao='=';while(!P3_1);}if(!P3_0){fuhao='/';while(!P3_0);}
}
void display(int num1){
n4=num1%10;
n3=num1/10%10;
n2=num1/100%10;
n1=num1/1000%10;
P2=0x01;
P0=duan[n1];
DelayXms(4);
P2=0x02;
P0=duan[n2];
DelayXms(4);
P2=0x04;
P0=duan[n3];
DelayXms(4);
P2=0x08;
P0=duan[n4];
DelayXms(4);
}
void DelayXms(unsigned int x) //@12.000MHz
{ unsigned char i, j;
while(x--)
{ i = 2;
j = 239;
do{while (--j);
}while (--i);
}
}
```
