//
// Created by light on 19-11-3.
//

#include <iostream>

using namespace std;

// non-explicit-one-argument ctor
class Fraction
{
public:
 // non-explicit-one-argument ctor 可以把别的东西转换为Fraction这种
 Fraction(int num, int den = 1) : m_numerator(num), m_denominator(den) {}

 Fraction operator+(const Fraction &f)
 {
 return Fraction(this->m_numerator + f.m_numerator);
 }

 void getNumAndDen()
 {
 cout << m_numerator << " " << m_denominator << endl;
 }

private:
 int m_numerator; // 分子
 int m_denominator; // 分母
};

// explicit-one-argument ctor
class Fraction1
{
public:
 // explicit-one-argument ctor 可以把别的东西转换为Fraction这种
 explicit Fraction1(int num, int den = 1) : m_numerator(num), m_denominator(den) {}

 Fraction1 operator+(const Fraction1 &f)
 {
 return Fraction1(this->m_numerator + f.m_numerator);
 }

 void getNumAndDen()
 {
 cout << m_numerator << " " << m_denominator << endl;
 }

private:
 int m_numerator; // 分子
 int m_denominator; // 分母
};

class P
{
public:
 P(int a, int b)
 {
 cout << "P(int a,int b)\n";
 }

 P(int a, int b, int c)
 {
 cout << "non-explicit P(int a,int b,int c)\n";
 }
 explicit P(int a, int b, int c, int d)
 {
 cout << "explicit P(int a,int b,int c,int d)\n";
 }
};

void fp(const P &)
{
}

int main()
{
 Fraction f(3, 5);
 Fraction ff = f + 3; // 会将3转换为(3,1) 隐式转换
 ff.getNumAndDen();

 // 如果不想编译器进行隐式转换,可以在前面添加explicit关键字

 // c++2.0之前explicit只禁止"存在单一实参"转换
 // c++2.0之后explicit可以进制"多个实参"转换
 // Fraction1 f1(3,5);
 // Fraction1 f2 = f1+3; // 会将3转换为(3,1) 不会隐式转换 error: no match for ‘operator+’ (operand types are ‘Fraction1’ and ‘int’)
 // f2.getNumAndDen();
 P p1 = {77, 5};
 P p2 = {77, 5, 89};
 // P p3 = {77, 5, 89,99}; //error: converting to ‘P’ from initializer list would use explicit constructor ‘P::P(int, int, int, int)’
 return 0;
}