Question

保留const Student stud(101,78.5) 怎么改正确

#include<iostream>
using namespace std;
class Student
{
public:
Student(int n,float s):num(n),score(s){}
void change(int n,float s){num=n;score=s;}
void display() {cout<<num<<" "<<score<<endl;}
private:
mutable int num;
mutable float score;
};
int main()
{
const Student stud(101,78.5);
stud.display();
stud.change(101,80.5);
stud.display();
return 0;
}

Answer 1

成员函数说明加上const才能由const的对象调用。
class Student
{
public:
Student(int n,float s):num(n),score(s){}
void change(int n,float s) const {num=n;score=s;}
void display() const {cout<<num<<" "<<score<<endl;}
private:
mutable int num;
mutable float score;
};