类的自动转换和强制类型转换

来源：互联网发布：中信建投期货软件编辑：程序博客网时间：2024/05/28 16:14

一、自动转换

1、通过构造函数来实现

2、支持隐式转换，如果构造函数前使用explicit关键字，将关闭隐式转换

3、实现了将其他数据类型转换为类

二、强制类型转换——转换函数

1、转换函数原型：

operator typeName();

typeName为要转换的类型，如int，double。。。

2、注意隐式转换时避免二义性

3、实现了将类转换为其他数据类型

#ifndef WEIGHT_H#define WEIGHT_Hclass Weight{    public:        Weight(double kg = 0);        ~Weight();        double getWeight() const;        operator int() const;  //转化函数 class to int    protected:    private:        double kg;};#endif // WEIGHT_H

weight.cpp

#include "Weight.h"Weight::Weight(double kg){    this->kg = kg;}Weight::~Weight(){    //dtor}double Weight::getWeight() const{    return kg;}Weight::operator int() const{    return int(kg);}

main.cpp

#include <iostream>#include "Weight.h"using namespace std;int main(){    Weight weightTest;    weightTest = 3.4;  //implicit ,  weightTest = (Weight)3.2  cast number to class    int num = weightTest; //implicit ,  num = (int)weightTest  cast class to number    cout << "weightTest"<<(double)weightTest << endl;    cout <<"num = "<<num<<endl;    return 0;}

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