题目：
1.除了整数以外，还要支持真分数的四则运算，真分数的运算
2.运算符为 +, −, ×, ÷
3.并且要求能处理用户的输入，并判断对错
4.使用 -n 参数控制生成题目的个数。
解决思路:
1.根据用户输入的参数,生成n道分数运算题、
2.通过用户输入的答案，判断对错
3.打印题目的文件生成——使用fprinrf语句实现
程序代码：
#include<stdio.h>
#include<iostream.h>
#include<stdlib.h>
#include<time.h>
void boom()
{
FILE *fpt;
fpt = fopen("四则运算.txt","w");
float x,y;
int z,t;
int first_num,second_num,third_num,fourth_num;
srand(time(NULL));
int n;
float d;
float daan[100];
cout<<"列出数学题数量?"<<endl;
cin>>n;
cout<<"--------------------------------------------"<<endl;
for(int i=0;i<n;i++)
{
z=rand()%4;
first_num=rand()%10;
second_num=rand()%10;
third_num=rand()%10;
fourth_num=rand()%10;
if (second_num==1)
{
x=(float)first_num;
}
else if(first_num>second_num)
{
t=first_num;
first_num=second_num;
second_num=t;
}
x=(float)first_num/second_num;
if (fourth_num==1)
{
y=(float)third_num;
}
else if(third_num>fourth_num)
{
t=third_num;
third_num=fourth_num;
fourth_num=t;
}
y=(float)third_num/fourth_num;
z=rand()%4;
switch(z)
{
case 0:
cout<<i+1<<"、 "<<first_num<<"/"<<second_num<<"+"<<third_num<<"/"<<fourth_num<<"="<<" ";
fprintf(fpt,"%d 、 %d/%d + %d/%d = \n",i+1,first_num,second_num,third_num,fourth_num);
daan[i+1]=x+y;
break;
case 1:
cout<<i+1<<"、 "<<first_num<<"/"<<second_num<<"-"<<third_num<<"/"<<fourth_num<<"="<<" ";
fprintf(fpt,"%d 、 %d/%d - %d/%d = \n",i+1,first_num,second_num,third_num,fourth_num);
daan[i+1]=x-y;
break;
case 2:
cout<<i+1<<"、 "<<first_num<<"/"<<second_num<<"*"<<third_num<<"/"<<fourth_num<<"="<<" ";
fprintf(fpt,"%d 、 %d/%d * %d/%d = \n",i+1,first_num,second_num,third_num,fourth_num);
daan[i+1]=x*y;
break;
case 3:
if(y!=0)
{
cout<<i+1<<"、 "<<first_num<<"/"<<second_num<<"÷"<<third_num<<"/"<<fourth_num<<"="<<" ";
fprintf(fpt,"%d 、 %d/%d ÷ %d/%d = \n",i+1,first_num,second_num,third_num,fourth_num);
fclose(fpt);
}
else
{
i=i-1;
}
daan[i+1]=(float)x/y;
break;
}
if((i+1)%3==0)
{
for(int c=0;c<=1;c++)
{
cout<<endl;
}
}
if((i+1)==n)
{
cout<<endl;
}
}
for(i=1;i<=n;i++)
{
cout<<"请作答:"<<endl;
cout<<i<<"、";
cin>>d;
if(d==daan[i])
{
cout<<"回答正确"<<endl;
cout<<endl;
}
else
{
cout<<"回答错误，正确答案为："<<" "<<daan[i]<<endl;
cout<<endl;
}
}
}
int main()
{
boom();
int c;
cout<<"还继续要答题吗？（0：继续 1：退出）"<<endl;
cin>>c;
if(c==0)
{
cout<<endl;
main();
}
else
{
cout<<endl;
return 0;
}
return 0;
}
运行截图：
