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c++第九章-（运算符重载）

2024-07-11 05:44:16   224人阅读

一些规则

1.c++不允许用户自己定义新的运算符，只能对已有的c++运算符进行重载。

2.除了五个运算符不允许重载外，其他运算符允许重载：

  • .成员访问运算符
  • *成员指针访问运算符
  • ::与运算符
  • sizeof尺寸运算符
  • ?:条件运算符

3.重载运算符必须和用户定义的自定义类型的对象一起使用。（也就是说，参数不能全部都是c++的标准类型，这样约定是为了防止用户修改用于标准类型结构的运算符性质）

4.为什么运算符重载函数有两个参数，只需有一个参数？

其实是有一个参数是隐含着的，运算符函数是用this指针隐式地访问类对象的成员。

class Complex{public:    Complex();    Complex(double r,double i);    Complex operator+(Complex &d);    void print();private:    double real;    double imag;};Complex::Complex(){    real = 0;    imag = 0;}Complex::Complex(double r,double i){    real = r;    imag = i;}Complex Complex::operator+(Complex &d){    Complex c;        c.real = real + d.real;    c.imag = imag + d.imag;        return c;}void Complex::print(){    std::cout << "(" << real << "," << imag << "i)\n";}int main(int argc, const char * argv[]){    Complex c1(3,4),c2(5,-10),c3;    c3 = c1 + c2;        std::cout << "c1 = ";    c1.print();    std::cout << "c2 = ";    c2.print();    std::cout << "c1 + c2 = ";    c3.print();        return 0;}

 有理数运算demo

#include <stdlib.h>class Rational{public:    Rational(int num,int denom);//num用于分子，denom用于分母        Rational operator+(Rational rhs);    Rational operator-(Rational rhs);    Rational operator*(Rational rhs);    Rational operator/(Rational rhs);        void print();private:    void normalize();//负责对分数简化    int numerator;    int denominator;};Rational::Rational(int num,int denom){    this->numerator = num;    this->denominator = denom;        normalize();}Rational Rational::operator+(Rational rhs){    int a = numerator;    int b = denominator;    int c = rhs.numerator;    int d = rhs.denominator;        int e = a * b + c * d;    int f = b * d;        return Rational(e,f);}Rational Rational::operator-(Rational rhs){    rhs.numerator = -rhs.numerator;    return operator+(rhs);}Rational Rational::operator*(Rational rhs){    int a = numerator;    int b = denominator;    int c = rhs.numerator;    int d = rhs.denominator;        int e = a * c;    int f = b * d;        return Rational(e,f);}Rational Rational::operator/(Rational rhs){    int t = rhs.numerator;    rhs.numerator = rhs.denominator;    rhs.denominator = t;        return operator*(rhs);}void Rational::print(){    if (numerator % denominator == 0)    {        std::cout << numerator / denominator;    }    else    {        std::cout << numerator << "/" << denominator;    }}void Rational::normalize(){    if (denominator < 0)//确保分母为正    {        numerator = -numerator;        denominator = -denominator;    }    //欧几里德算法    int a = abs(numerator);//求绝对值    int b = abs(denominator);        //求最大公约数    while (b > 0)    {        int t = a % b;        a = b;        b = t;    }        //分子、分母分别除于最大公约数得到最简化分数    numerator /= a;    denominator /= a;}int main(int argc, const char * argv[]){    Rational f1(2,16);    Rational f2(7,8);        Rational res = f1 + f2;    f1.print();    std::cout << " + ";    f2.print();    std::cout << " = ";    res.print();    std::cout << "\n";        res = f1 - f2;    f1.print();    std::cout << " - ";    f2.print();    std::cout << " = ";    res.print();    std::cout << "\n";        res = f1 * f2;    f1.print();    std::cout << " * ";    f2.print();    std::cout << " = ";    res.print();    std::cout << "\n";        res = f1 / f2;    f1.print();    std::cout << " / ";    f2.print();    std::cout << " = ";    res.print();    std::cout << "\n";    return 0;}

 


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