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?1.运算符重载：
? ? 赋予运算符有操作自定义类型数据的功能
? ? 运算符重载的本质就是函数调用?
? ? 函数返回值由运算之后的值进行决定
? ??函数名 ? ?: operator 加上重载运算符组成函数名 如operator+，operator-?
? ? 具体参数个数为需要重载函数的形式
#include<iostream>
#include<string>
using namespace std;
class Fox
{
public:
Fox(string name="", int age = 0) : name(name), age(age) {}//构造函数
void printf()
{
cout << name << "\t" << age << endl;
}
bool operator>(Fox fox) //重载大于号
{
if (this->age>fox.age)
{
return true;
}
else
{
return false;
}
}
friend Fox operator+(Fox fox1, Fox fox2);//友元函数的声明
protected:
string name;
int age;
};
Fox operator+(Fox fox1, Fox fox2)//友元重载+号的实现
{
return Fox(fox1.name + fox2.name, fox1.age + fox2.age);
}
int main()
{
Fox yueyue("月", 18);
Fox yueyue2("月2", 13);
Fox yueyue3;
if (yueyue>yueyue2)
{
cout << "yueyue大" << endl;
}
else
{
cout << "yueyue不大" << endl;
}
yueyue3 = yueyue + yueyue2;
yueyue3.printf();
while (1);
return 0;
}
? ? 2.特殊运算符重载?
? ? cin类型 istream类对象
? ? cout类型 ostream类对象
? ? 流运算符 << >>?
? ?其他运算符
? ? = () -> [] 只能采用类的成员函数形式重载
? ?流重载采用友元方式
? ?. ?.* ??: ? :: 运算符不能重载
#include<iostream>
#include<string>
using namespace std;
class Fox
{
public:
Fox(string name="", int age = 0) : name(name), age(age) {}//构造函数
void printf()
{
cout << name << "\t" << age << endl;
}
friend istream& operator>>(istream& in, Fox& fox);//友元函数的声明
friend ostream& operator<<(ostream& out, Fox& fox);//友元函数的声明
protected:
string name;
int age;
};
istream& operator>>(istream& in,Fox& fox)//因为要修改数据类型所以传引用
{
in >> fox.name >> fox.age;
return in;//为了能做连续输入的操作 返回 in
}
ostream& operator<<(ostream& out, Fox& fox)
{
out << fox.name << "\t" << fox.age;
return out;//为了能做连续的输出 所以返回 ostream 流
}
int main()
{
Fox fox1;
Fox fox2;
cin >> fox1 >> fox2;
cout << fox1 << fox2;
while (1);
return 0;
}
? ?++ -- 运算符重载。
? 在重载函数中填入无用的int 型参数? 代表该为后置加加
#include<iostream>
#include<string>
using namespace std;
class Fox
{
public:
Fox(string name="", int age = 0) : name(name), age(age) {}//构造函数
void printf()
{
cout << name << "\t" << age << endl;
}
friend istream& operator>>(istream& in, Fox& fox);//友元函数的声明
friend ostream& operator<<(ostream& out, Fox& fox);//友元函数的声明
Fox operator++(int)//带表该为后置加加
{
return Fox(name,age++);
}
Fox operator++()//带表该为前置加加
{
return Fox(name, ++age);
}
protected:
string name;
int age;
};
istream& operator>>(istream& in,Fox& fox)//因为要修改数据类型所以传引用
{
in >> fox.name >> fox.age;
return in;//为了能做连续输入的操作 返回 in
}
ostream& operator<<(ostream& out, Fox& fox)
{
out << fox.name << "\t" << fox.age;
return out;//为了能做连续的输出 所以返回 ostream 流
}
int main()
{
Fox fox1;
Fox fox2;
Fox fox3;
Fox fox4;
cin >> fox1 >> fox2;
cout << fox1 << fox2;
fox3 = fox2++;
cout << fox3;
fox4=++fox1;
cout << fox4;
while (1);
return 0;
}
? ?文本重载 语法是 unsigned long long ?operator""
? ?例子
#include<iostream>
#include<string>
using namespace std;
unsigned long long operator""_day(unsigned long long num)
{
return 24 * num;
}
int main()
{
int num = 1_day;//算出一个值 返回给变量
return 0;
}
综合：
#include<iostream>
#include<string>
using namespace std;
class Double
{
public:
Double(double num = 0.0) :num(num) {}//构造函数
double& data() //修改这个类中数据成员提供的接口
{
return num;
}
friend istream& operator>>(istream&in, Double& Vdouble);
friend ostream& operator<<(ostream&out, Double& Vdouble);
Double operator+(const Double& num2)//加入const 是为了常量相加
{
return Double(this->num + num2.num);//通过类去做重载
}
friend Double operator-(const Double& num1, const Double& num2)
{
return Double(num1.num - num2.num);
}
Double operator+=(const Double& num1) //我们的数据类型相加
{
return Double(this->num + num1.num);
}
Double operator+=(const double& num1) //和默认的类型数据相加
{
return Double(this->num + num1);
}
Double operator++(int) //后置加加
{
return Double(this->num++);
}
Double operator++()//前置加加
{
return Double(++(this->num));
}
int * operator&() //放回一个地址
{
return (int*)(&this->num);
}
Double operator-()
{
return(-this->num);
}
protected:
double num;
};
istream& operator>>(istream& in, Double& Vdouble)
{
in >> Vdouble.num;
return in;
}//流重载
ostream& operator<<(ostream& out, Double& Vdouble)
{
out << Vdouble.num;
return out;
}
int main()
{
Double arr1(1.1);//1.1
Double arr2 = 2.1;//2.1
Double arr3;//0.0
Double arr=1.5;//1.5
arr3 = arr1 - arr;//arr3=1.1-1.5
cout << arr3 << arr1 << arr;
cin >> arr1;
cout << arr1;
arr2 = ++arr;//arr2=2.5
cout << arr2;//2.5
cout << arr;//arr=2.5
cout << &arr << endl;
arr = -arr;
cout << arr;//-2.5
while (1);
return 0;
}
[]运算符重载
#include<iostream>
using namespace std;
class Array
{
public:
Array(int size)
{
arraybest = new int(size);
}
~Array()
{
delete[] arraybest;
}
int& operator[](int i)//重载中括号
{
return arraybest[i];
}
protected:
int* arraybest;
};
int main()
{
while (1);
return 0;
}
作业：
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