最后报错，没有与“<<”所匹配的操作符

Question

问题遇到的现象和发生背景

问题相关代码，请勿粘贴截图

运行结果及报错内容

我的解答思路和尝试过的方法

我想要达到的结果

```c++
#include<iostream>
#include<string>
using namespace std;
class croster
{
    static int count;
private:
    string name;
    int Math;
    int English;
    int Sum;
public:
    croster(string na = "undef", int m = 100, int e = 100);
    void display();
    int cumulation();
    static void dis()
    {
        cout << "count" << endl;
    }
};
int croster::count = 100;
croster::croster(string na, int m, int e):name(na),Math(m),English(e)
{
    cout << "Welcome new class." << endl;
    Sum = Math + English;
    count--;
}
void croster::display()
{
    cout << name << endl;
    cout << "Math:" << Math << endl;
    cout << "English:" << English << endl;
    cout << "Sum:" << Sum << endl;
}
int croster::cumulation()
{
    Sum = Math + English;
    return Sum;
}
int main()
{
    cout << "Number of all student=" << croster::dis() << endl;
    croster list[3];
    cout << "Number of all student=" << list[1].dis ()<< endl;
    croster stu_A;
    cout << "Number of all student=" << stu_A.dis ()<< endl;
    cout << "Number of all student=" << croster::dis() << endl;
    return 0;
}
报错的是主函数里面每行输出函数里面的，第二个“<<”符号

```

Answer 1

当然出错啦，静态成员函数dis返回值是void！