求解C++编程中遇到的问题

Question

#include
#include
using namespace std;
class Stud
{private:
int no;
char name;
float deg;
public:
static float sum;
static int num;
static float avg();
static void disp();
};
float Stud::sum=0.0;
int Stud::num=0;
Stud::Stud(int m,char n,float d)
{no=m;
name=n;
deg=d;
sum+=deg;
}

float Stud::avg()
{return sum/num;}

void Stud::disp()
{cout<<"学号："<<no<<endl;
cout<<"姓名："<<name<<endl;
cout<<"成绩："<<deg<<endl;
cout<<"平均分："<<avg()<<endl;
}

int main()
{
Stud s1(101,"Xiaoming",84),s2(102,"Xiaohong",94),s3(103,"Xiaofang",87);
s1.avg();
s1.disp();
s2.avg();
s2.disp();
s3.avg();
s3.disp();
return 0;
}

Answer 1

构造函数重载需要在类中声明才能使用，另外一个是非静态成员变量不能直接在静态成员函数中使用，可以采用类指针（模拟类似this指针）解决。

 #include <iostream>
using namespace std;

class Stud
{
    private:
        int no;
        char* name;
        float deg;
    public:
        Stud(int m, char* n, float d);
        static float sum;
        static int num;
        static float avg(Stud* stud);
        static void disp(Stud* stud);
};

float Stud::sum = 0.0;
int Stud::num = 3;

Stud::Stud(int m, char* n, float d)
{
    no=m;
    name=n;
    deg=d;
    sum+=deg;
}

float Stud::avg(Stud* stud)
{
    return stud->sum/stud->num;
}

void Stud::disp(Stud* stud)
{
    cout<<"学号："<<stud->no<<endl;
    cout<<"姓名："<<stud->name<<endl;
    cout<<"成绩："<<stud->deg<<endl;
    cout<<"平均分："<<stud->avg(stud)<<endl;
}

int main()
{
    Stud s1(101,"Xiaoming",84),s2(102,"Xiaohong",94),s3(103,"Xiaofang",87);
    s1.avg(&s1);
    s1.disp(&s1);
    s2.avg(&s2);
    s2.disp(&s2);
    s3.avg(&s3);
    s3.disp(&s3);
    return 0;
}