Question

这在Visual Studio 2015中运行良好，但在使用MinGw时运行不佳。为什么？如何解决？

错误信息：

不匹配＆＃39;运营商＆lt;＆lt;＆＃39; （操作数类型是＆＃39; std :: ostream {aka std :: basic_ostream}＆＃39; Fraction＆＃39;）werjiorqq.cpp / werjiorqq / src第106行C / C ++问题

不匹配＆＃39;运营商＆lt;＆lt;＆＃39; （操作数类型是＆＃39; std :: ostream {aka std :: basic_ostream}＆＃39; Fraction＆＃39;）werjiorqq.cpp / werjiorqq / src第107行C / C ++问题

不匹配＆＃39;运营商＆lt;＆lt;＆＃39; （操作数类型是＆＃39; std :: ostream {aka std :: basic_ostream}＆＃39; Fraction＆＃39;）werjiorqq.cpp / werjiorqq / src第108行C / C ++问题

不匹配＆＃39;运营商＆lt;＆lt;＆＃39; （操作数类型是＆＃39; std :: ostream {aka std :: basic_ostream}和＆＃39; Fraction＆＃39;）werjiorqq.cpp / werjiorqq / src第109行C / C ++问题

没有匹配函数来调用＆＃39; Fraction :: Fraction（Fraction）＆＃39; werjiorqq.cpp / werjiorqq / src第71行C / C ++问题

没有匹配函数来调用＆＃39; Fraction :: Fraction（Fraction）＆＃39; werjiorqq.cpp / werjiorqq / src第88行C / C ++问题

#include <iostream>    
#include <cmath>

using namespace std;
int gcd(int m, int n) {

    if (m%n == 0)
        return n;
    else
        return gcd(n, m%n);
}

int  preGcd(int m, int n) {

    int absm = abs(m);
    int absn = abs(n);

    int g = gcd(absm, absn);
    return g;

}


class Fraction {
    int m, n;
public:
    Fraction() {
    }
    Fraction(Fraction& f) {
        m = f.getM();
        n = f.getN();
    }
    Fraction(int m, int n) {
        this->m = m;
        this->n = n;
    }

    friend ostream& operator<< (ostream& out,Fraction& f) {
        cout << f.m << '/' << f.n << endl;
        return out;
    }

    int getM() {
        return m;
    }
    int getN() {
        return n;
    }

    void reduction() {
        int g;
        if (n > m)
            g = preGcd(n, m);
        else
            g = preGcd(m, n);
        m /= g;
        n /= g;
    }

    friend Fraction operator+ (Fraction f1,Fraction f2) {
        int nn = f1.n*f2.n;
        int nm = f1.m*f2.n + f2.m*f1.n;
        Fraction *p = new Fraction(nm, nn);
        p->reduction();
        return *p;
            }
    friend Fraction operator- (Fraction f1, Fraction f2) {
        f2.m = (-f2.m);
        return operator+ (f1, f2);
    }
    friend Fraction operator* (Fraction f1, Fraction  f2) {
        /*cout << f1;
        cout << f2;*/
        int nn = f1.n*f2.n;
        int nm = f1.m*f2.m;
        Fraction *p = new Fraction(nm, nn);
        p->reduction();
        return *p;
    }

    friend Fraction operator/ (Fraction f1, Fraction f2) {
        int temp = f2.m;
        f2.m = f2.n;
        f2.n = temp;

        return operator*(f1, f2);
    }

    void revenue() {
        cout << n << '/' << m << endl;
    }

};



int main() {
    int a, b, c, d;
    cin >> a >> b >> c >> d;

    Fraction f1(a, b);
    Fraction f2(c, d);

    cout << f1 + f2;
    cout << f1 - f2;
    cout << f1*f2;
    cout << f1 / f2;
    f1.revenue();
}

Answer 1

您需要尽可能申请const。例如：

Fraction(const Fraction &);
friend ostream& operator<< (ostream& out, const Fraction& f);
int getM() const;
int getN() const;

等

代码有什么问题？

1 个答案: