C++之类的比较运算符的重载

比较运算符的重载通常有两种方式:

第一:作为成员函数重载

以前几章的Student类为例:

<span style="font-family:Microsoft YaHei;font-size:18px;">class Student{
private:
	string name;
	int age;
	float score;
	//const成员变量
	const int max_length;
	//定义静态成员变量
	static int number; 
	static float total;
public:
	//Student(string name,int age,float score);
	//有const成员变量,必须有参数初始化列表,
	Student(string name,int age,float score):name(name),age(age),score(score),max_length(3){
		number++;
		total += score;
	}
	//拷贝构造函数中,const成员变量的初始化,用初始化列表
	Student(const Student & s):max_length(3){
		this ->name = s.name;
		this ->age = s.age;
		this ->score = s.score;
		number++;
		total += score;
	};
	~Student();
	void setName(string n);
	string getName()const;
	void setAge(int a);
	int getAge() const;
	void setScore(float s);
	float getScore() const;
	void say() const;
	static float getAverage();
	
	//运算符的重载
	bool operator== (const Student &s) const;
	//用友元函数重载等于 运算符
	//friend bool operator== (const Student &s,const Student&s1);
};
</span>

这里可以把(opetator==)理解为"成员函数名"。

bool Student::operator==(const Student &s) const {
	return this->name == s.name && this->age == s.age && this ->score == s.score;
}

第二:作为友元函数重载

 bool operator== (const Student &s,const Student&s1){
	 return (s.age == s1.age && s.name == s1.name && s.score == s1.score);
}