C++构造函数的用法

/*声明和实现构造函数*/


/*
class Human
{
public:
	Human();//声明一个构造函数
}

1.构造函数既可以在类声明内实现,也可以在类声明外实现

(1)在类声明内实现如下:
class Human
{
public:
	Human()
	{
	
	}

};

(2)在类声明外实现如下:
class Human
{
public:
	Human();
};

Human::Human()
{
}
*/

/*构造函数主要用于初始化*/

#include <iostream>
using namespace std;

class Human
{
	private:
		string name;
		int age;

	public:
	Human()
	{
		age = 1;
		cout<<"Constructed an instance of class Human"<<endl;
	}
	
	void SetName(string humanName)
	{
		name = humanName;
	}
	
	void SetAge(int humansAge)
	{
		age = humanAge;	
	}
	
	void IntroduceSelf()
	{
		cout<<"I am "+name << " and "+age<<endl;
	}
	
	
}




int main()
{
	Human firstWoman;
	firstWoman.SetName("Eve");
	forstWoman.SetAge(28);
	firstWoman.IntroduceSelf();
	return 0;
}




/*包含多个构造函数的Human类*/

**注意**
构造函数必须和类名相同

#include<iostream>
using namespace std;

class Human
{
private:
	string name;
	int age;
	
public:
	Human()
	{
		age = 0;
		cout<<"Overloaded constructor creates ";
		cout<<"Default constructor: name and age not set "<<endl;
	}
	
	Human(string humansName,int humansAge)
	{
		name = humansName;
		age = humansAge;
		cout<< "Overloaded constructor creates";
		cout<<name<< " of "<< age <<" years"<<endl;
	}
};


int main()
{
	Human firstMan;
	Human firstWoman(" Eve",20);

	return 0;
}