计算与软件工程 作业二
作业二
作业要求
https://edu.cnblogs.com/campus/jssf/infor_computation17-31/homework/10402)
遇到的问题
- 对于年级的选择不能放在一个程序里，逻辑顺序没有办法很好的运用。
- 难中易程度不能很好的分开。
- 计算答题时间有问题，只有等程序结束后在后台查看。程序的计算时间与实际情况不符
代码
#include<iostream>
#include<stdlib.h>
#include<time.h>
#include <string.h>
#include<cstdlib>
using namespace std;
int a;
int ri = 0;//计算回答的正确率，定义全局变量 ri 来计算回答正确的题数
//divisor (int a,int b) 函数通过辗转相除法求分子和分母的最大公约数
int divisor (int a,int b)
{
int temp;
if(a<b)
{
temp=a;
a=b;
b=temp;
}
while(b!=0)
{
temp=a%b;
a=b;
b=temp;
}
return a;
}
//CheckResult(char result[]) 函数来判断输入的答案是否正确
int CheckResult(char result[])
{
char answer[10] ;
cin>>answer;
if(strcmp(answer,result)==0)
{
cout<<"回答正确"<<endl<<endl;
ri++;
}
else
{
cout<<"回答错误,正确答案为"<<result<<endl<<endl;
}
return 0;
}
//integer() 函数来生成整数的四则运算
void integer()
{
int x,y,z,temp;
char result[10];
srand(time(NULL));
x = rand() % 10;
y = rand() % 10+1;
z = rand()%4;
switch(z)
{
case 0 :
cout<<x<<" + "<<y<<"=";
temp = x + y;
sprintf(result, "%d", temp);
break;
case 1 :
if(x<y)
{
temp=x;
x=y;
y=temp;
}
cout<<x<<" - "<<y<<"=";
temp = x - y;
sprintf(result, "%d", temp);
break;
case 2 :
cout<<x<<" * "<<y<<"=";
temp = x * y;
sprintf(result, "%d", temp);
break;
case 3 :
cout<<x<<" ÷"<<y<<"=";
if(x%y==0)
{
temp = x / y;
sprintf(result, "%d", temp);
}
else
{
temp = divisor(x,y);
x = x/temp;
y = y/temp;
sprintf(result, "%d/%d", x, y);
}
break;
}
CheckResult(result) ;
}
// fraction() 函数来生成分数的四则运算
void fraction()
{
int a,b,c,d,x,y,z,temp;
char result[10];
srand(time(NULL));
a = rand() % 10;
b = rand() % 10+1;
c = rand() % 10;
d = rand() % 10+1;
z = rand() % 4;
if(a>b)
{
temp=a;
a=b;
b=temp;
}
if(c>d)
{
temp=c;
c=d;
d=temp;
}
switch(z)
{
case 0 :
cout<<a<<"/"<<b<<" + "<<c<<"/"<<d<<"=";
x = a*d+b*c;
y = b*d;
temp = divisor(x,y);
x = x/temp;
y = y/temp;
if(y==1)
{
sprintf(result, "%d", x);
}
else
{
sprintf(result, "%d/%d", x, y);
}
break;
case 1 :
if(a*d<b*c)
{
temp = a;
a = c;
c = temp;
temp = b;
b = d;
d = temp;
}
cout<<a<<"/"<<b<<" - "<<c<<"/"<<d<<"=";
x = a*d-b*c;
y = b*d;
temp = divisor(x,y);
x = x/temp;
y = y/temp;
sprintf(result, "%d/%d", x, y);
break;
case 2 :
cout<<a<<"/"<<b<<" * "<<c<<"/"<<d<<"=";
if(a==0||c==0)
{
temp = 0;
sprintf(result, "%d", temp);
}
else
{
x = a*c;
y = b*d;
temp = divisor(x,y);
x = x/temp;
y = y/temp;
sprintf(result, "%d/%d", x, y);
}
break;
case 3 :
cout<<a<<"/"<<b<<" ÷"<<c<<"/"<<d<<"=";
if((a*d)%(b*c)==0)
{
x = a*d;
y = b*c;
temp = x / y;
sprintf(result, "%d", temp);
}
else
{
x = a*d;
y = b*c;
temp = divisor(x,y);
x = x/temp;
y = y/temp;
if(y==1)
{
sprintf(result, "%d", x);
}
else
{
sprintf(result, "%d/%d", x, y);
}
}
break;
}
CheckResult(result);
}
int main()
{
int n,q;
cout<<"输入要生成的题数:";
cin>>n;
for(int i=0;i<n;i++)
{
int a = rand()%2;
switch(a)
{
case 0: integer();break;
case 1: fraction();break;
}
}
q=(ri*100)/n;
cout<<"回答对了"<<ri<<"题"<<endl;
cout<<"正确率为:"<<q<<"%"<<endl<<endl;
clock_t start,finish;
start=clock();
cout << "花费的时间 " << endl;
finish=clock();
cout << finish-start << "/" << CLOCKS_PER_SEC << " (s) "<< endl;
system ("pause");
}
此程序没有混合运算，适用于低年级
//判断运算符的优先级函数
int Precede(char a, char b)
{
switch (a)
{
case '*':
case '/':
if ((b == '+') || (b == '-'))
{
return 1; //a的优先级高于b
}
else
{
return 0; //a的优先级等于b
}
case '+':
case '-':
if ((b == '*') || (b == '/'))
{
return -1; //a的优先级低于b
}
else
{
return 0;
}
default:
cout<<"运算符错误！"<<endl;
break;
}
}
int Operate(int j, int k, char operater)
{
switch (operater)
{
case '+':
return k + j;
break;
case '-':
return k - j;
break;
case '*':
return k * j;
break;
case '/':
return k / j;
break;
default: printf("运算错误！\n");
break;
}
}
int calculate(int len, char *expStr)
{
//表达式异常处理，注意len <= 0要加括号
if ((len <= 0 ) || (expStr == NULL))
{
cout<<"表达式为空！"<<endl;
}
int i = 0, j = 0, k = 0;
std::stack<int> date;
std::stack<char> operate;
while (i < len)
{
if ((expStr[i] >= '0') && (expStr[i] <= '9'))
{
date.push(expStr[i] - '0');
i++;
}
else if ((expStr[i] == '+') || (expStr[i] == '-') || expStr[i] == '*' || expStr[i] == '/')
{
if (operate.empty())
{
operate.push(expStr[i]);
i++;
}
else
{
//与栈顶运算符判断优先级
switch (Precede(expStr[i], operate.top()))
{
case 0:
case -1: //栈顶运算符优先级高
j = date.top();
date.pop();
k = date.top();
date.pop();
date.push(Operate(j, k , operate.top()));
operate.pop();
//i++;
break;
case 1: //栈运算符顶优先级低
operate.push(expStr[i]);
i++;
break;
default:
cout<<"优先级判断错误！"<<endl;
break;
}
}
}
else
{
cout<<"表达式无法识别！";
break;
}
}
while (!operate.empty())
{
j = date.top();
date.pop();
k = date.top();
date.pop();
date.push(Operate(j, k , operate.top()));
operate.pop();
}
return date.top();
}
int main()
{
int len = 0; int i= 0, input_flag = 0;
while (!input_flag)
{
cout<<"请输入表达式的长度：";
input_flag = scanf("%d", &len);
if (!input_flag)
{
printf("输入有误，仅可输入数字！\n");
}
flushall();
}
char *expStr = (char *)malloc(len * sizeof(char));
input_flag = 0;
while (!input_flag)
{
printf("请输入表达式：");
for (i = 0; i < len; i++)
{
input_flag = scanf("%c", &expStr[i]);
//scanf("%c", &expStr[i]);
/*
if ((i < len) && (expStr[i] == '\n'))
{
printf("长度不够，请重新输入：");
i = 0;
}
*/
if (!input_flag)
{
cout<<"表达式输入有误！\n";
flushall();
break;
}
}
}
cout<<"表达式的计算结果为：%d\n"<< calculate(len, expStr);
system("pause");
return 0;
}
此程序段有混合运算，适用于高年级。但不能自动出题。
