C++：为什么使用初始化列表

C++

• 只有初始化列表可以初始化const常量，如果我们需要在构造函数处初始化常量，需要这样写。
• 初始化列表只能应用在构造函数中
• 初始化列表早于构造函数执行，下面以Teacher类举例：

Teacher.h

#include <iostream>
#include <string>
using namespace std;
class Teacher
{
public:
    Teacher(string name="Jim",int age=1,int m=100);
    void setName(string _name);
    string getName();
    void setGender(string _gender);
    string getGender();
    void setAge(int _age);
    int getAge();
    void teach();
    int getMax();
private:
    string m_strName;
    string m_strGender;
    int m_iAge; 
    const int m_iMax;
};

Teacher.cpp

#include "Teacher.h"
Teacher::Teacher(string name,int age,int m):m_strName(name),m_iAge(age),m_iMax(m) 
{
    cout<<"Teacher(string name,int age,int m):m_strName(name),m_iAge(age),m_iMax(m) "<<endl;
}
int Teacher::getMax()
{
    return m_iMax;
}
void Teacher::setName(string _name)
{
    m_strName=_name;
}
string Teacher::getName()
{
    return m_strName;
}
void Teacher::setGender(string _gender)
{
    m_strGender=_gender;
}
string Teacher::getGender()
{
    return m_strGender;
}
void Teacher::setAge(int _age)
{
    m_iAge=_age;
}
int Teacher::getAge()
{
    return m_iAge;
}
void Teacher::teach()
{
    cout<<"现在上课了"<<endl;
}

demo.cpp

#include "Teacher.h"
int main()
{
    Teacher t1("merry",12,150);
    cout<<t1.getName()<<"\t"<<t1.getAge()<<"\t"<<t1.getMax()<<endl;
    return 0;
}