C++之类的const成员变量和const成员函数
const成员变量 【C++之类的const成员变量和const成员函数】如果类中有const成员变量，那么初始化的时候，只能用参数初始化列表构造函数
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;
};
以下是一个完整的例子
#include
#include
using namespace std;
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,必须用参数初始化列表,
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();
void setAge(int a);
int getAge();
void setScore(float s);
float getScore();
void say();
static float getAverage();
};
/*
注意，如果构造函数的形参和 类的成员变量名字一样，必须采用 this -> name = name ,而不可以 写成 name = name，
但是如果用参数初始化列表写构造函数，就可以避免这个问题
*//*
Student::Student(string name,int age,float score){
this->name = name;
this ->age = age;
this ->score = score;
number++;
total += score;
}
*//*
Student::Student(const Student & s){
this ->name = s.name;
this ->age = s.age;
this ->score = s.score;
}
*/Student::~Student(){}
string Student::getName(){
return this->name;
}
int Student::getAge(){
return this->age;
}
float Student::getScore(){
return this ->score;
}void Student::setName(string n){
this ->name = n;
}void Student::setAge(int a){
this ->age =a ;
}void Student::setScore(float s){
this->score =s;
}void Student::say(){
cout << this->name <<" : " << this->age <<" : " << this ->score << " : " << Student::number < const成员函数
#include
#include
using namespace std;
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();
};
/*
注意，如果构造函数的形参和 类的成员变量名字一样，必须采用 this -> name = name ,而不可以 写成 name = name，
但是如果用参数初始化列表写构造函数，就可以避免这个问题
*//*
Student::Student(string name,int age,float score){
this->name = name;
this ->age = age;
this ->score = score;
number++;
total += score;
}
*//*
Student::Student(const Student & s){
this ->name = s.name;
this ->age = s.age;
this ->score = s.score;
}
*/Student::~Student(){}
string Student::getName()const{
return this->name;
}
int Student::getAge() const{
return this->age;
}
float Student::getScore()const{
return this ->score;
}void Student::setName(string n){
this ->name = n;
}void Student::setAge(int a){
this ->age =a ;
}void Student::setScore(float s){
this->score =s;
}void Student::say()const{
cout << this->name <<" : " << this->age <<" : " << this ->score << " : " << Student::number < 推荐阅读
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