#include<iostream>
#include<time.h>
#include<fstream>
#define random() (rand()%100)
using namespace std; void main()
{
ofstream outfile;
outfile.open("a.txt");
char add='+';
char sec='-';
char min='*';
char div='/';
int length;
cout<<"请输入题目数量：";
cin>>length; bool printway;
cout<<"请选择打印方式 <1>txt文档 <0>屏幕：";
cin>>printway; bool divsion;
cout<<"请选择是否有除法<1>有除法 <0>无除法：";
cin>>divsion; bool bracket;
cout<<"请选择是否有括号<1>有括号 <0>无括号：";
cin>>bracket; bool negative;
cout<<"加减有无负数<1>有负数 <0>无负数：";
cin>>negative; bool remainder;
cout<<"除法有无余数<1有余数> <0>无余数：";//先计算结果，再根据条件输出
cin>>remainder; int widestart;
int wideend;
cout<<"数值范围(起始---终止)：";
cin>>widestart;
cin>>wideend; int i;//循环参数
int j;//循环参数
int firstnum;
int secondnum;
int thirdnum;
int fourthnum;
int fifthnum;
srand((int)time(NULL)); for( i=;i<length;i++) //循环输出length个算式
{
firstnum=rand()%wideend+widestart;
secondnum=rand()%wideend+widestart;
thirdnum=rand()%wideend+widestart;
fourthnum=rand()%wideend+widestart;
fifthnum=rand()%wideend+widestart; if(negative)/*if negative =1 当加减存在负数时*/
{
if(printway) //若输出到txt
{
outfile<<firstnum;
outfile<<add;
}
else
{
cout<<firstnum;
cout<<add;
}
if(bracket) //若选择有括号输出左括号
{
if(printway)
{
outfile<<"(";
}
else
{
cout<<"(";
}
} //输出左括号结束
if(printway)
{
outfile<<secondnum;
outfile<<sec;
outfile<<thirdnum;
outfile<<min;
outfile<<fourthnum;
}
else
{
cout<<secondnum;
cout<<sec;
cout<<thirdnum;
cout<<min;
cout<<fourthnum;
} //输出除法之前的数
if(bracket)
{
if(printway)
{
outfile<<")";
}
else
{
cout<<")";
}
} //输出右括号 /*******************************************************************************************有除法有括号没有余数**/
if(divsion) //有除法的情况
{
if(bracket)//if have bracket,panduan shifou you yushu
{
if (!remainder) //如果没有余数
{
for(i=;;)
{
int result=( secondnum-thirdnum*fourthnum ) /fifthnum;
if( result==)
{
if(printway)
{
outfile<<div<<fifthnum;
}
else
{
cout<<div<<fifthnum;
}
break;
}
else
{
fifthnum=rand()%wideend+widestart;
}
}
}
} /**************************************************************************************有除法无括号无余数********/
else//meiyou kuohao panduan shifou you yushu
{ if (!remainder) //没有余数的情况
{ for(i=;;)
{
int result1=(thirdnum*fourthnum ) / fifthnum;
if( result1 ==) //判断是否有余数，若没有，则输出
{
if(printway)
{
outfile<<div<<fifthnum<<"="<<endl;
}
else
{
cout<<div<<fifthnum<<"="<<endl;
}
break;
}
else
{
fifthnum=rand()%wideend+widestart; //若有余数。则重新生成除数
}
}
} }
} if(printway)
{
outfile<<"="<<endl;
}
else
{
cout<<"="<<endl;
} } else/* negative=0 没有负数的情况*/
{
if(printway)
{
outfile<<firstnum;
outfile<<add;
}
else
{
cout<<firstnum;
cout<<add;
}
if(bracket)
{
if(printway)
{
outfile<<"(";
}
else
{
cout<<"(";
}
}
if(printway)
{
outfile<<secondnum;
outfile<<sec;
outfile<<thirdnum;
outfile<<min;
outfile<<fourthnum;
}
else
{
cout<<secondnum;
cout<<sec;
cout<<thirdnum;
cout<<min;
cout<<fourthnum;
}
for(j=;;) /* a+b-c*d/e 则判断b-c*d不能有负数 ，若有负数则循环至 没有*/
{
secondnum=rand()%wideend+widestart;
if(secondnum>(thirdnum*fourthnum))
{
if(printway)
{
outfile<<firstnum<<add;
}
else
{
cout<<firstnum<<add;
}
if(bracket)
{
if(printway)
{
outfile<<"(";
}
else
{
cout<<"(";
}
}
if(printway)
{
outfile<<secondnum<<sec<<thirdnum<<min<<fourthnum;
}
else
{
cout<<secondnum<<sec<<thirdnum<<min<<fourthnum;
}
} //循环结束 if(divsion)
{
if(printway)
{
outfile<<")"<<div;
}
else
{
cout<<")"<<div;
}
if(bracket)//if have bracket,panduan shifou you yushu
{
if (!remainder)
{
for(i=;;)
{
int flag=firstnum+( secondnum-thirdnum*fourthnum ) /fifthnum ;//有括号的情况下判断是否有余数
if( flag ==)
{
if(printway)
{
outfile<<fifthnum;
}
else
{
cout<<fifthnum;
}
break;
}
else
{
fifthnum=rand()%wideend+widestart;
}
}
}
else
{
if(printway)
{
outfile<<")";
outfile<<div<<fifthnum;
}
else
{
cout<<")";
cout<<div<<fifthnum;
}
}
}
else//meiyou kuohao panduan shifou you yushu
{
if (!remainder)
{
for(i=;;)
{
int flag1= (thirdnum*fourthnum )/fifthnum;
if( flag1 ==) //没有括号的情况下判断余数是否为0
{
if(printway)
{
outfile<<div<<fifthnum;
}
else
{
cout<<div<<fifthnum;
}
break;
}
else
{
fifthnum=rand()%wideend+widestart;
}
}
}
else
{
if(printway)
{
outfile<<")";
outfile<<div<<fifthnum;
}
else
{
cout<<")";
cout<<div<<fifthnum;
} }
}
break;
} if(printway)
{
outfile<<"="<<endl;
}
else
{
cout<<"="<<endl;
}
} }
}
outfile.close();
}
我的设计思路是：
先输出一个菜单：多少道题目，输出到屏幕还是文档，是否有除法，是否有括号，是否有负数，是否有余数，以及随机数的范围这几个方面。这几个方面的控制是由bool类型控制的，是为“1”，否为“2”。
我的主函数里面最外层是用一个循环来控制题目的数量。
接下来是一个if。。。else语句，将加减是否有负数进行分类，有负数进入if语句，没有负数进入else语句。
我所设置的括号位置是固定的，都是a+(b-c*d)/e=的样式。有括号的就输出，不选择有括号就输出a+b-c*d/e。
范围带入到rand函数就可以了，输出到屏幕用的是outfile输出，还剩除法和余数两项。
有除法才会有余数，括号又可以影响运算顺序，所以得到嵌套：
if（有负数）
{
if（有除法）
if（有括号）
if（没有余数）
}
else
{
if（有除法）
if（有括号）
if（没有余数）
}