引言：
本文利用STC89C52设计制作了一个限时问答机，能够通过显示设备显示简单的随机算式1，并在规定时间内通过按键读取用户输入，并判断输入结果的正误以及输入是否超时。完整代码请参考：https://github.com/PPPerry/Time-limited-question-and-answer-machine
1.硬件模块
电源采用 5V 实验电源供电
4×4矩阵键盘按键输入
LCD1602显示屏
2.软件模块
顶层代码：
#include <stdlib.h>
#include <reg52.h>
#include "lcd.h"
#include "key.h"
#include "time.h"
//12.8第一次更新： 定时器开启提前 删去两个timestart
//12.8第二次更新： 避免出现长按按键超过3s的bug
//12.8第三次更新： 三位数选项
//12.8第四次更新： 时间限制选项
u8 code result1[]="true :-)";
u8 code result2[]="false :-(";
u8 code result3[]="time out!!!";
u8 code mode1[]="MODE SELECT";
u8 code mode2[]="TIME SELECT";
u8 code over11[]="YOU WIN!!!";
u8 code over12[]="CONGRATULATIONS!";
u8 code over21[]="Game over";
u8 code over22[]="...";
u8 timenum,p,r,limittime,t,f;
void delay(u16 ms)
{
int x,y;
for(x=ms;x>0;x--)
{
for(y=110;y>0;y--);
}
}
void timestart() //定时器重装初值
{
TH0=(65536-50000)/256;
TL1=(65536-50000)%256;
timenum=0;
}
/*void randnum(char*str) //随机计算式产生函数
{
u16 n;
for(n=0;n<5;n++)
{
if(n==2) //随机加减号
{
if(timenum%2)
*(str+n)='+';
else
*(str+n)='-';
}
else if(n==0||n==3) //保证个位数不为0
{
do
{
srand((u16)timenum);
*(str+n)=rand()%9;
}while(*(str+n)==0);
}
else
{
srand((u16)timenum);
*(str+n)=rand()%9;
}
}
*(str+5)='=';
}*/
u8 keyboard(u8 key) //键盘对应符号
{
switch(key)
{
case 2:return '1';
case 3:return '2';
case 4:return '3';
case 9:return '-';
case 6:return '4';
case 7:return '5';
case 8:return '6';
case 10:return '7';
case 11:return '8';
case 12:return '9';
case 15:return '0';
default:return ' ';
}
}
void main()
{
u8 key;
u8 cal[12];
u16 n;
int answer;
r=1; //记录是否超时的状态参数
TR0=1; //开启定时器
while(1)
{
t=0;f=0;
lcdinit();
write_exact(11,0x00,mode1);
key=keyscan(); //矩阵键盘，返回值为按下的按键
if(key==1) //开机键，模式为2位数
{
lcdinit();
write_exact(11,0x00,mode2);
timeinit();
limittime=' ';
while(limittime==' ') //时间限制
{
key=keyscan();limittime=keyboard(key);}
while(1)
{
lcdinit();
if(f==5){
write_exact(9,0x00,over21);write_exact(3,0x40,over22);timestart();while(timenum!=60);break;}
if(t==5){
write_exact(10,0x00,over11);write_exact(16,0x40,over12);timestart();while(timenum!=60);break;}
r=1;
key=' ';
cal[6]=' ';
cal[7]=' ';
cal[8]=' ';
for(n=0;n<5;n++)
{
if(n==2) //随机加减号
{
if((p-'0')%2)
cal[n]='+';
else
cal[n]='-';
}
else if(n==0||n==3) //保证十位数不为0
{
srand((p-'0')+n);
cal[n]='1'+rand()%8;
}
else
{
srand((p-'0')+2*n);
cal[n]='0'+rand()%9;
}
}
cal[5]='=';
if(cal[2]=='+')
answer=(cal[0]-'0')*10+(cal[1]-'0')+(cal[3]-'0')*10+(cal[4]-'0'); //算出正确答案
else if(cal[2]=='-')
answer=(cal[0]-'0')*10+(cal[1]-'0')-(cal[3]-'0')*10-(cal[4]-'0');
if((answer<0&&answer>-10)||(answer>=10&&answer<=99)) //判断位数
{
cal[8]=0;} //置为0后下面代码的while判断就可以跳过
else if(answer>=0&&answer<10)
{
cal[7]=0;cal[8]=0;} //三位数或负两位数不需置0
write_exact(6,0x00,cal);
writetf();
timestart();
if(cal[6]==' ') //输入
{
while(key==' ')
{
key=keyscan();
if(!r)break;
if(limittime>3&&(limittime-t-'0')<3){
if(timenum==(limittime-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}else{
if(timenum==(limittime-t-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}
}
if(r!=0&&key!=' ')
{
cal[6]=keyboard(key);
write_com(0x80+0x06);
write_data('0'+(cal[6]-'0'));
}
}
key=' ';
if(r==0)continue;
if(cal[7]==' ')
{
while(key==' ')
{
key=keyscan();
if(!r)break;
if(limittime>3&&(limittime-t-'0')<3){
if(timenum==(limittime-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}else{
if(timenum==(limittime-t-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}
}
if(r!=0&&key!=' ')
{
cal[7]=keyboard(key);
write_com(0x80+0x07);
write_data('0'+(cal[7]-'0'));
}
}
key=' ';
if(r==0)continue;
if(cal[8]==' ')
{
while(key==' ')
{
key=keyscan();
if(!r)break;
if(limittime>3&&(limittime-t-'0')<3){
if(timenum==(limittime-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}else{
if(timenum==(limittime-t-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}
}
if(r!=0&&key!=' ')
{
cal[8]=keyboard(key);
write_com(0x80+0x08);
write_data('0'+(cal[8]-'0'));
}
}//完成输入
if(r) //未超时,开始判断正误
{
timestart();
if(answer<=-10)
{
if(cal[6]=='-'&&((cal[7]-'0')*10+(cal[8]-'0'))==-answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
else if(answer<0&&answer>-10)
{
if(cal[6]=='-'&&(cal[7]-'0')==-answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
else if(answer>=0&&answer<10)
{
if((cal[6]-'0')==answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
else if(answer>=10&&answer<=99)
{
if(((cal[6]-'0')*10+(cal[7]-'0'))==answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
else if(answer>=100)
{
if((cal[6]-'0')*100+(cal[7]-'0')*10+(cal[8]-'0')==answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
}
}
}
if(key==5) //开机键,模式为3位数
{
lcdinit();
write_exact(11,0x00,mode2);
timeinit();
limittime=' ';
while(limittime==' ') //时间限制
{
key=keyscan();limittime=keyboard(key);}
while(1)
{
lcdinit();
if(f==5){
write_exact(9,0x00,over21);write_exact(3,0x40,over22);timestart();while(timenum!=40);break;}
if(t==5){
write_exact(10,0x00,over11);write_exact(16,0x40,over12);timestart();while(timenum!=40);break;}
r=1;
key=' ';
cal[8]=' ';
cal[9]=' ';
cal[10]=' ';
cal[11]=' ';
for(n=0;n<7;n++)
{
if(n==3) //随机加减号
{
if((p-'0')%2)
cal[n]='+';
else
cal[n]='-';
}
else if(n==0||n==4) //保证百位数不为0
{
srand((p-'0')+n);
cal[n]='1'+rand()%8;
}
else
{
srand((p-'0')+2*n);
cal[n]='0'+rand()%9;
}
}
cal[7]='=';
if(cal[3]=='+')
answer=(cal[0]-'0')*100+(cal[1]-'0')*10+(cal[2]-'0')+(cal[4]-'0')*100+(cal[5]-'0')*10+(cal[6]-'0'); //算出正确答案
else if(cal[3]=='-')
answer=(cal[0]-'0')*100+(cal[1]-'0')*10+(cal[3]-'0')-(cal[4]-'0')*100-(cal[5]-'0')*10-(cal[6]-'0');
if((answer<0&&answer>-10)||(answer>=10&&answer<=99)) //判断位数
{
cal[10]=0;cal[11]=0;} //置为0后下面代码的while判断就可以跳过
else if(answer>=0&&answer<10)
{
cal[9]=0;cal[10]=0;cal[11]=0;}
else if((answer>=100&&answer<1000)||(answer>-100&&answer<=-10))
{
cal[11]=0;}
write_exact(8,0x00,cal);
writetf();
timestart();
if(cal[8]==' ') //输入
{
while(key==' ')
{
key=keyscan();
if(!r)break;
if(limittime>3&&(limittime-t-'0')<3){
if(timenum==(limittime-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}else{
if(timenum==(limittime-t-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}
}
if(r!=0&&key!=' ')
{
cal[8]=keyboard(key);
write_com(0x80+0x08);
write_data('0'+(cal[8]-'0'));
}
}
key=' ';
if(r==0)continue;
if(cal[9]==' ')
{
while(key==' ')
{
key=keyscan();
if(!r)break;
if(limittime>3&&(limittime-t-'0')<3){
if(timenum==(limittime-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}else{
if(timenum==(limittime-t-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}
}
if(r!=0&&key!=' ')
{
cal[9]=keyboard(key);
write_com(0x80+0x09);
write_data('0'+(cal[9]-'0'));
}
}
key=' ';
if(r==0)continue;
if(cal[10]==' ')
{
while(key==' ')
{
key=keyscan();
if(!r)break;
if(limittime>3&&(limittime-t-'0')<3){
if(timenum==(limittime-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}else{
if(timenum==(limittime-t-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}
}
if(r!=0&&key!=' ')
{
cal[10]=keyboard(key);
write_com(0x80+0x0A);
write_data('0'+(cal[10]-'0'));
}
}
key=' ';
if(r==0)continue;
if(cal[11]==' ')
{
while(key==' ')
{
key=keyscan();
if(!r)break;
if(limittime>3&&(limittime-t-'0')<3){
if(timenum==(limittime-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}else{
if(timenum==(limittime-t-'0')*20)
{
timenum=0;
write_exact(11,0x40,result3);
while(timenum!=40);
timestart();
r=0;
f++;
break;
}
}
}
if(r!=0&&key!=' ')
{
cal[11]=keyboard(key);
write_com(0x80+0x0B);
write_data('0'+(cal[11]-'0'));
}
}//完成输入
if(r) //未超时,开始判断正误
{
timestart();
if(answer<=-100)
{
if(cal[8]=='-'&&((cal[9]-'0')*100+(cal[10]-'0')*10+(cal[11]-'0'))==-answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
else if(answer<=-10&&answer>-100)
{
if(cal[8]=='-'&&((cal[9]-'0')*10+(cal[10]-'0'))==-answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
else if(answer<0&&answer>-10)
{
if(cal[8]=='-'&&(cal[9]-'0')==-answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
else if(answer>=0&&answer<=9)
{
if((cal[8])==answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
else if(answer>=10&&answer<100)
{
if((cal[8]-'0')*10+(cal[9]-'0')==answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
else if(answer>=100&&answer<1000)
{
if((cal[8]-'0')*100+(cal[9]-'0')*10+(cal[10]-'0')==answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
else if(answer>=1000)
{
if((cal[8]-'0')*1000+(cal[9]-'0')*100+(cal[10]-'0')*10+(cal[11]-'0')==answer){
write_exact(8,0x40,result1);t++;while(timenum!=40);}
else{
write_exact(9,0x40,result2);f++;while(timenum!=40);}
}
}
}
}
}
}
void Time0()interrupt 1
{
TH0=(65536-50000)/256;
TL1=(65536-50000)%256;
timenum++;
p++;if(p==100)p++;
}
3.说明
本题出自 电子科技大学 2018/12 CIE训练赛。
随机算式包括随机两位数算式和随机三位数算式 ↩︎