利用树莓派实现简单的计算器

在实验板上实现一个简单的计算器，要求在实验板的命令行运行程序，输入两个100以内的数字以及运算符 （+，-，*，/），然后计算结果并在数码管上显示计算结果。

电路设计如下：

 

实物连接：

 

代码如下：

#include <wiringPi.h>
#include <stdio.h>
#include <stdlib.h>

#define DIGIT1 9
#define DIGIT2 13
#define DIGIT3 12
#define DIGIT4 8
#define BTN0 10
#define BTN1 11

#define true 1

char digit[10][8] =   //the loop-running bar in the left windows
    {
        {0,0,0,1,0,0,1,0},//0
        {1,0,0,1,1,1,1,1},//1
        {0,0,1,1,0,1,0,0},//2
        {0,0,0,1,1,1,0,0},//3
        {1,0,0,1,1,0,0,1},//4
        {0,1,0,1,1,0,0,0},//5
        {1,1,0,1,0,0,0,0},//6
        {0,0,0,1,1,1,1,1},//7
        {0,0,0,1,0,0,0,0},//8
        {0,0,0,1,1,0,0,0}//9
    };
char sign[8]={1,1,1,1,1,1,0,1};//-
char nosign[8]={1,1,1,1,1,1,1,1};

void main() 
{
    int pin;
    //int m = 0, n = 0;
    //int flag = 1;
    int chip = 0;
    int chip0,chip1,chip2,chip3;
    int run = 0;
    unsigned int time0 = 0, time1 = 0;
    int a,b;
    char c;
    int result;
    int num1,num2;
    int negative = 0;
    int iteration = 500;
    int i;

    if (wiringPiSetup () == -1) //test the install status of wiringPi
    {
        exit (1) ;
    }

    for (pin = 0 ; pin < 8 ; ++pin) 
    {
        pinMode (pin, OUTPUT) ;
        digitalWrite(pin, HIGH);
   }

    pinMode(DIGIT1, OUTPUT);
    pinMode(DIGIT2, OUTPUT);
    pinMode(DIGIT3, OUTPUT);
    pinMode(DIGIT4, OUTPUT);
   // pinMode(BTN0, INPUT); //The start button
    pinMode(BTN1, INPUT); //The stop/stop button

    while (true)
    {
       scanf("%d%c%d",&a,&c,&b);
       switch(c){
           case '+':result = a+b;
           break;
           case '-':result = a-b;
           break;
           case '*':result = a*b;
           break;
           case '/':result = a/b;
           break;
       }
       printf("%d\n",result);
        if(result<0){
           negative=1;
           result = -result;
       }
           
       else
           negative=0;
       result = result%100;   //only display 2-digit
       num1 = result/10;
       num2 = result%10;
       //printf("%d %d\n",num1,num2);
      
       
       for(i=0;i<iteration;i++){
           if(i%3==0){
               if(negative){
                   for (pin = 0; pin < 8; pin++)
                    {
                        digitalWrite(pin, sign[pin]);
                    }
                
               }
               else{
                   for (pin = 0; pin < 8; pin++)
                    {
                        digitalWrite(pin, nosign[pin]);
                    }
               }
               digitalWrite(DIGIT1,1);
           }
           else if(i%3==1){
                for (pin = 0; pin < 8; pin++)
                {
                    digitalWrite(pin, digit[num1][pin]);
                }
                digitalWrite(DIGIT2,1);
           }
           else{
               for (pin = 0; pin < 8; pin++)
                {
                    digitalWrite(pin, digit[num2][pin]);
                }
                digitalWrite(DIGIT3,1);
           }
           delay(10);
           digitalWrite(DIGIT1,0);
           digitalWrite(DIGIT2,0);
           digitalWrite(DIGIT3,0);
       }
       
    }

}

功能说明：支持基本的四则运算，使用前三个数码管显示结果，第一个显示符号，如果结果为正，不显示，如果为负，显示“-”，每个计算结果会在数码管上显示5秒左右，当数码管熄灭后可以进行下一次的运算，结果需要三位数显示的话会对100进行取余后进行显示。

运行，输入算术表达式进行验证