void Test函数是错误的 想知道怎么改

分数计算器

#include<bits/stdc++.h>
using namespace std;
class Rational{
    int numerator;                                            
    int denominator;
    void normalize_();
public:
    Rational(int numerator=0, int denominator=0);  
    friend Rational operator+(Rational r1, Rational r2);        
    friend Rational operator-(Rational r1, Rational r2);
    friend Rational operator*(Rational r1, Rational r2);
    friend Rational operator/(Rational r1, Rational r2);
    friend istream &operator>>(istream &in, Rational& r);        
    friend ostream &operator<<(ostream &out, Rational& r);    
    friend bool operator==(Rational r1,Rational r2);
    Rational normalize();      
};
Rational::Rational(int num, int denom)
{
    numerator = num;
    if (denominator != 0)   denominator = denom;                // 分母不能为0,在流输入运算符重载中也有定义
    else denominator = 1;
    normalize_();
}
Rational Rational::normalize()                            
{                                                                //求出分子和分母的最大公约数，用欧几里得算法
    int a = abs(numerator);
    int b = abs(denominator);
    while (b > 0)
    {
        int t = a % b;
        a = b;
        b = t;
    }
    Rational R(numerator / a, denominator / a);
    return R;
}
Rational operator+(Rational r1, Rational r2)                    //重载加法运算符，分数的加法
{
    int a = r1.numerator;
    int b = r1.denominator;
    int c = r2.numerator;
    int d = r2.denominator;
    int e = a * d + b * c;
    int f = b * d;
    Rational R(e, f);
    return R;
}
void Rational::normalize_()
{

                                                                //求出分子和分母的最大公约数，用欧几里得算法
    int a = abs(numerator);
    int b = abs(denominator);
    while (b > 0)
    {
        int t = a % b;
        a = b;
        b = t;
    }
    numerator /= a;
    denominator /= a;
}

Rational operator-(Rational r1, Rational r2)                    //重载减法运算符,函数结构和加法一致，返回加法运算
{
    int a = r1.numerator;
    int b = r1.denominator;
    int c = r2.numerator;
    int d = r2.denominator;
    int e = a * d - b * c;
    int f = b * d;
    Rational R(e, f);
    return R;
}

Rational operator*(Rational r1, Rational r2)                    //重载乘法运算符，调用初始化类是化简了分数
{
    int a = r1.numerator;
    int b = r1.denominator;
    int c = r2.numerator;
    int d = r2.denominator;
    int e = a * c;
    int f = b * d;
    Rational R(e, f);
    return R;
}

Rational operator/(Rational r1, Rational r2)                    //返回乘法运算函数体
{
    int t = r2.numerator;
    r2.numerator = r2.denominator;
    r2.denominator = t;
    return operator*(r1, r2);
}
bool operator==(Rational r1,Rational r2)
{
     if(r1.numerator ==r2.numerator && r1.denominator ==r2.denominator )
        return true;
    else
        return false;
}
istream &operator>>(istream &in, Rational& r)                    //流输入运算符
{
    in >> r.numerator>> r.denominator;                            //避免除0错误，进行判断，分母为0时程序结束
    if (r.denominator != 0)
        return in;
    else
    {
        cout << "输入有误";
        exit(0);
    }
}

ostream &operator<<(ostream &out, Rational& r)                    //流输出运算符
{
    if (r.numerator%r.denominator == 0)                            //进行判断，当为一个整数时，改变输出
        out << r.numerator / r.denominator;
    else
        out << r.numerator << "\\"<<r.denominator;
        return out;
}
void Test(){//有问题
   cout<<"共10道题，做100以内的加减运算，满分100分:\n";
   int score=0;
   char op;
   for(int i=0;i<=9;i++)
{
    int m1 = rand() % 10 + 1; //生成1-100的随机数
    int n1 = rand() % 100 + 1;
    int m2 = rand() % 10 + 1;
    int n2 = rand() % 100 + 1;
    Rational a(m1,n1),b(m2,n2);
    int m3 = rand()%20-10;
    int n3 = rand()%20-10;
    int m4 = rand()%20-10;
    int n4 = rand()%20-10;
    Rational c(m3,n3),d(m4,n4);
    Rational answer;
    op=rand()%4; //产生随机加减乘除运算的4个值
    switch(op)
 {
    case 0:
    answer=a+b;
    cout<<a<<"加上"<<b<<"等于";
    break;
    case 1:
    cout<<a<<"减去"<<b<<"等于";
    answer =a-b;
    break;
    case 2:
    answer=c*d;
    cout<<c<<"乘以"<<d<<"等于";
    break;
    case 3:
    answer=c/d;
    cout<<c<<"除以以"<<d<<"等于";
    break;    
}
      Rational temp;
    cin>>temp; //输入用户计算值
    if(answer==temp) //比较用户计算值
{
score+=10;
}
else
{
cout<<"此题做错了\n";
cout<<"正确答案为:"<<answer<<endl;
}
}
cout<<"你的最后得分是:"<<score<<endl;
}
int main(){
    Rational r1(1,2);
    Rational r2(1,3);
    Rational r3(1,4);
do{
    system("cls");
    cout << "\t这是一个简单的计算器程序，可以实现以下功能，请按对应的按键(1-5)\n\n\n";
    cout << "\t=========================MENU===========================\n";
    cout << "\t1:有理数加法，以0结束\n";
    cout << "\t2:有理数减法，以0结束\n";    
    cout << "\t3:有理数乘法，以0结束\n";
    cout << "\t4:有理数除法，以0结束\n";
    cout << "\t5测试：每次10题 由计算机随机出题 每题10分 共100分";
    cout << "\t0:退出程序\n\n:";
    cout << "\t请您选择:";
    int choise;
    cin >> choise;
    if (choise == 1)
    {   
        cout << "first number r1:"<<endl;
        cin >> r1;
        cout << "last number r2:"<<endl;
        cin >> r2;
        r3=r1+r2;
        cout<<r3<<endl; 
    }
    else if (choise == 2)
    {   cout << "first number r1:"<<endl;
        cin >> r1;
        cout << "last number r2:"<<endl;
        cin >> r2;
        r3=r1-r2;
        cout<<r3<<endl;
    }
    else if (choise == 3)
    {   cout << "first number r1:"<<endl;
        cin >> r1;
        cout << "last number r2:"<<endl;
        cin >> r2;
        r3=r1*r2;
        cout<<r3<<endl;
    }
    else if (choise == 4)
    {   cout << "first number r1:"<<endl;
        cin >> r1;
        cout << "last number r2:"<<endl;
        cin >> r2;
        r3=r1/r2;
        cout<<r3<<endl; 
    }
    else if(choise == 5){
        Test();
    }
    else if (choise == 0) //用户选0则结束调用函数
    {
            cout << "\n\n\t欢迎下次继续使用计算器!\n";
            break;
     }
    else
    {
            cout << "\n\t输入错误，请按任意键继续!\n";
    }system("pause");
}while(1);
}

运行完计算是错误的 哪里错了捏

Rational answer;===这行有问题，也就是    Rational 类的构造函数 Rational(int numerator=0, int denominator=0);有问题

当定义answer时，由于没有传入参数，导致两个参数值默认都是0，这样在normalize_();函数中就崩溃了，因为 numerator /= a;
denominator /= a;时，a是0，所以出现除零错误。
在构造函数中对参数为零进行判断，为0则不进行normalize_()函数处理，或者增加一个无参构造函数，什么也不用做，然后当前构造函数中去掉默认值。这样也可以

using namespace std;
class Rational{
    int numerator;                                            
    int denominator;
    void normalize_();
public:
    Rational() {}
    Rational(int numerator, int denominator);  
    friend Rational operator+(Rational r1, Rational r2);        
    friend Rational operator-(Rational r1, Rational r2);
    friend Rational operator*(Rational r1, Rational r2);
    friend Rational operator/(Rational r1, Rational r2);
    friend istream &operator>>(istream &in, Rational& r);        
    friend ostream &operator<<(ostream &out, Rational& r);    
    friend bool operator==(Rational r1,Rational r2);
    Rational normalize();      
};
Rational::Rational(int num, int denom)
{
    numerator = num;
    if (denominator != 0)   denominator = denom;                // 分母不能为0,在流输入运算符重载中也有定义
    else denominator = 1;
    normalize_();
}
Rational Rational::normalize()                            
{                                                                //求出分子和分母的最大公约数，用欧几里得算法
    int a = abs(numerator);
    int b = abs(denominator);
    while (b > 0)
    {
        int t = a % b;
        a = b;
        b = t;
    }
    Rational R(numerator / a, denominator / a);
    return R;
}
Rational operator+(Rational r1, Rational r2)                    //重载加法运算符，分数的加法
{
    int a = r1.numerator;
    int b = r1.denominator;
    int c = r2.numerator;
    int d = r2.denominator;
    int e = a * d + b * c;
    int f = b * d;
    Rational R(e, f);
    return R;
}
void Rational::normalize_()
{
 
                                                                //求出分子和分母的最大公约数，用欧几里得算法
    int a = abs(numerator);
    int b = abs(denominator);
    while (b > 0)
    {
        int t = a % b;
        a = b;
        b = t;
    }
    numerator /= a;
    denominator /= a;
}
 
Rational operator-(Rational r1, Rational r2)                    //重载减法运算符,函数结构和加法一致，返回加法运算
{
    int a = r1.numerator;
    int b = r1.denominator;
    int c = r2.numerator;
    int d = r2.denominator;
    int e = a * d - b * c;
    int f = b * d;
    Rational R(e, f);
    return R;
}
 
Rational operator*(Rational r1, Rational r2)                    //重载乘法运算符，调用初始化类是化简了分数
{
    int a = r1.numerator;
    int b = r1.denominator;
    int c = r2.numerator;
    int d = r2.denominator;
    int e = a * c;
    int f = b * d;
    Rational R(e, f);
    return R;
}
 
Rational operator/(Rational r1, Rational r2)                    //返回乘法运算函数体
{
    int t = r2.numerator;
    r2.numerator = r2.denominator;
    r2.denominator = t;
    return operator*(r1, r2);
}
bool operator==(Rational r1,Rational r2)
{
     if(r1.numerator ==r2.numerator && r1.denominator ==r2.denominator )
        return true;
    else
        return false;
}
istream &operator>>(istream &in, Rational& r)                    //流输入运算符
{
    in >> r.numerator>> r.denominator;                            //避免除0错误，进行判断，分母为0时程序结束
    if (r.denominator != 0)
        return in;
    else
    {
        cout << "输入有误";
        exit(0);
    }
}
 
ostream &operator<<(ostream &out, Rational& r)                    //流输出运算符
{
    if (r.numerator%r.denominator == 0)                            //进行判断，当为一个整数时，改变输出
        out << r.numerator / r.denominator;
    else
        out << r.numerator << "\\"<<r.denominator;
        return out;
}
void Test(){//有问题
   cout<<"共10道题，做100以内的加减运算，满分100分:\n";
   int score=0;
   char op;
   for(int i=0;i<=9;i++)
{
    int m1 = rand() % 10 + 1; //生成1-100的随机数
    int n1 = rand() % 100 + 1;
    int m2 = rand() % 10 + 1;
    int n2 = rand() % 100 + 1;
    Rational a(m1,n1),b(m2,n2);
    int m3 = rand()%20-10;
    int n3 = rand()%20-10;
    int m4 = rand()%20-10;
    int n4 = rand()%20-10;
    Rational c(m3,n3),d(m4,n4);
    Rational answer;
    op=rand()%4; //产生随机加减乘除运算的4个值
    switch(op)
 {
    case 0:
    answer=a+b;
    cout<<a<<"加上"<<b<<"等于";
    break;
    case 1:
    cout<<a<<"减去"<<b<<"等于";
    answer =a-b;
    break;
    case 2:
    answer=c*d;
    cout<<c<<"乘以"<<d<<"等于";
    break;
    case 3:
    answer=c/d;
    cout<<c<<"除以以"<<d<<"等于";
    break;    
}
      Rational temp;
    cin>>temp; //输入用户计算值
    if(answer==temp) //比较用户计算值
{
score+=10;
}
else
{
cout<<"此题做错了\n";
cout<<"正确答案为:"<<answer<<endl;
}
}
cout<<"你的最后得分是:"<<score<<endl;
}
int main(){
    Rational r1(1,2);
    Rational r2(1,3);
    Rational r3(1,4);
do{
    system("cls");
    cout << "\t这是一个简单的计算器程序，可以实现以下功能，请按对应的按键(1-5)\n\n\n";
    cout << "\t=========================MENU===========================\n";
    cout << "\t1:有理数加法，以0结束\n";
    cout << "\t2:有理数减法，以0结束\n";    
    cout << "\t3:有理数乘法，以0结束\n";
    cout << "\t4:有理数除法，以0结束\n";
    cout << "\t5测试：每次10题 由计算机随机出题 每题10分 共100分";
    cout << "\t0:退出程序\n\n:";
    cout << "\t请您选择:";
    int choise;
    cin >> choise;
    if (choise == 1)
    {   
        cout << "first number r1:"<<endl;
        cin >> r1;
        cout << "last number r2:"<<endl;
        cin >> r2;
        r3=r1+r2;
        cout<<r3<<endl; 
    }
    else if (choise == 2)
    {   cout << "first number r1:"<<endl;
        cin >> r1;
        cout << "last number r2:"<<endl;
        cin >> r2;
        r3=r1-r2;
        cout<<r3<<endl;
    }
    else if (choise == 3)
    {   cout << "first number r1:"<<endl;
        cin >> r1;
        cout << "last number r2:"<<endl;
        cin >> r2;
        r3=r1*r2;
        cout<<r3<<endl;
    }
    else if (choise == 4)
    {   cout << "first number r1:"<<endl;
        cin >> r1;
        cout << "last number r2:"<<endl;
        cin >> r2;
        r3=r1/r2;
        cout<<r3<<endl; 
    }
    else if(choise == 5){
        Test();
    }
    else if (choise == 0) //用户选0则结束调用函数
    {
            cout << "\n\n\t欢迎下次继续使用计算器!\n";
            break;
     }
    else
    {
            cout << "\n\t输入错误，请按任意键继续!\n";
    }system("pause");
}while(1);
}

构造函数改一下，如下：

Rational::Rational(int num, int denom)
{
    numerator = num;
    if (denominator != 0)   denominator = denom;                // 分母不能为0,在流输入运算符重载中也有定义
    else denominator = 1;

    //这里处理一下都是负数的情况
    if (numerator < 0 && denominator < 0)
    {
        numerator = -numerator;
        denominator = -denominator;
    }

    if(num != 0) //这里排除分子是0的情况
        normalize_();
    else
    {
        numerator = 0;
        denominator = 1;
    }
}

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