#include <iostream.h> #include <string.h> class CStudent { public: CStudent(char *n, int a); ~CStudent(); static void SetAge(int age); private: char *name; int age; static int nTotalObj; }; int CStudent::nTotalObj = 0; CStudent::CStudent(char *n, int a) :age(a) { int nLen = strlen(n); name = new char[nLen+1]; strcpy(name,n); name[nLen] = '\0'; nTotalObj++; } CStudent::~CStudent() { delete[] name; nTotalObj--; } void CStudent::SetAge(int age) { this->age = age; } void main() { CStudent stu1("张三",25); CStudent str2("李四",26); cout<<"CStudent::nTotalObj="<<CStudent::nTotalObj<<endl; }

这是一个简单的 C++ 程序，定义了一个名为 CStudent 的类，包含了一个构造函数、一个析构函数、一个静态成员变量 nTotalObj 和一个静态成员函数 SetAge。程序的主函数 main 中创建了两个 CStudent 对象 stu1 和 stu2，输出 nTotalObj 的值。这个值表示在程序运行过程中创建的 CStudent 对象的数量。输出结果应该是：CStudent::nTotalObj=2。

相关问题

#include<iostream> using namespace std; class CStudent { private: char name[20]; int num; int Chinese, Physical, History; public: CStudent(); //无参构造函数的声明 CStudent(char* pName, int n, int C, int P, int History) ; //有参构造函数的声明 CStudent(const CStudent &stu) //拷贝构造函数 { strcpy(name, stu.name); num = stu.num; Chinese = stu.Chinese; Physical = stu.Physical; this->History = stu.History; } ~CStudent() {} char* getName() { return name; } int getNum() { return num; } int getChinese() { return Chinese; } int getPhysical() { return Physical; } int getHistory() { return History; } void operator=(CStudent stu); }; #include"student.h" #include <string> CStudent::CStudent(char *pName, int n, int C, int P, int History) { strcpy(name, pName); num = n; Chinese =C; Physical = P; this->History = History; } void CStudent::operator=(CStudent stu) { strcpy(name, stu.name); num = stu.num; Chinese = stu.Chinese; Physical = stu.Physical; History = stu.History; } int main() { cout << "用不带参数的构造函数创建对象：" << endl; CStudent s1; cout << sizeof(s1) << endl; cout << s1.getName() << " " << s1.getNum() << " " << s1.getChinese() << " " << s1.getHistory() << " " << s1.getPhysical() << endl; cout << "用带参数的构造函数创建对象：" << endl; CStudent s2("顾斌", 221404205, 120, 98, 70); cout << sizeof(s2) << endl; cout << s2.getName()<< "顾斌" << s2.getNum() << " " << s2.getChinese() << " " << s2.getHistory() << " " << s2.getPhysical() << endl; cout << "用拷贝初始化构造函数创建对象：" << endl; CStudent s3(s2); cout << sizeof(s3) << endl; cout << s3.getName()<< " " << s3.getNum() << " " << s3.getChinese() << " " << s3.getHistory() << " " << s3.getPhysical()<< endl; cout << "用=给对象赋值：" << endl; CStudent s4; s4 = s2; cout << s4.getName()<< " " << s4.getNum() << " " << s4.getChinese() << " " << s4.getHistory() << " " << s4.getPhysical() << endl; return 1; }

这段代码定义了一个名为 CStudent 的类，其中包括了无参构造函数、有参构造函数、拷贝构造函数和一个重载了赋值运算符的函数。主函数中创建了四个 CStudent 类的对象，并对这些对象进行了不同的操作。

在这段代码中，CStudent 类的成员变量有 name、num、Chinese、Physical 和 History，分别表示学生的姓名、学号、语文成绩、物理成绩和历史成绩。CStudent 类的成员函数包括了构造函数、拷贝构造函数、析构函数、获取成员变量值的函数和重载赋值运算符的函数。其中，构造函数可以有无参和有参两种形式，拷贝构造函数用于将一个已有对象的值赋给新创建的对象，赋值运算符的函数用于将一个对象的值赋给另一个对象。

在主函数中，首先创建了一个不带参数的 CStudent 类对象 s1，然后输出该对象的成员变量值。接着创建了一个带参数的 CStudent 类对象 s2，并输出其成员变量值。然后又创建了一个拷贝初始化的 CStudent 类对象 s3，并输出其成员变量值。最后，将 s2 对象的值赋给了 s4 对象，并输出 s4 的成员变量值。

#include<iostream> #include<string> using namespace std; class Cstudent{ private: int number; string name; static int total; static int actualtotal; public: Cstudent(string name); Cstudent(const Cstudent &p); ~Cstudent(); void showstudent(); int getnumber(){return number;} static int gettotal(){return total;} static int getactualtotal(){return actualtotal;} }; int Cstudent::total =0; int Cstudent::actualtotal=0; Cstudent::Cstudent(string name){ name = name; number = ++total; actualtotal++; } Cstudent::Cstudent(const Cstudent &p){ name = p.name; number = ++total; actualtotal++; } Cstudent::~Cstudent(){ actualtotal--; } void Cstudent::showstudent(){ cout << "student's name is " << name << "\tnumber is " <<number << endl; } int main(){ Cstudent stu[10]; for(int i=0;i<10;i++) stu[i].showstudent(); cout<<Cstudent::gettotal()<<stu[0].getactualtotal()<<endl;//两种访问静态方法 Cstudent *pa = new Cstudent("wang"); pa->showstudent(); delete pa; Cstudent *pb; pb = new Cstudent[10]; for(int i=0;i<10;i++) pb[i].showstudent(); delete[]pb; return 0; }哪里错了

在类的构造函数中，私有成员变量`name`应该使用`this->name`来表示当前对象的`name`成员变量，而不是将函数参数`name`赋值给自身`name`变量。因此，`Cstudent`类的构造函数应该改为：

Cstudent::Cstudent(string name){
    this->name = name;
    number = ++total;
    actualtotal++;
}

此外，在输出`Cstudent`对象的实际数量时，应该在两个数之间添加空格或者其他分隔符，否则两个数会被拼接在一起，难以区分。因此，`main`函数中输出实际数量的代码应该改为：

cout << Cstudent::gettotal() << " " << stu[0].getactualtotal() << endl;

以上修改后的完整代码如下：

#include<iostream>
#include<string>
using namespace std;

class Cstudent{
private:
    int number;
    string name;
    static int total;
    static int actualtotal;
public:
    Cstudent(string name);
    Cstudent(const Cstudent &p);
    ~Cstudent();
    void showstudent();
    int getnumber(){return number;}
    static int gettotal(){return total;}
    static int getactualtotal(){return actualtotal;}
};

int Cstudent::total =0;
int Cstudent::actualtotal=0;

Cstudent::Cstudent(string name){
    this->name = name;
    number = ++total;
    actualtotal++;
}

Cstudent::Cstudent(const Cstudent &p){
    name = p.name;
    number = ++total;
    actualtotal++;
}

Cstudent::~Cstudent(){
    actualtotal--;
}

void Cstudent::showstudent(){
    cout << "student's name is " << name << "\tnumber is " <<number << endl;
}

int main(){
    Cstudent stu[10];
    for(int i=0;i<10;i++)
        stu[i].showstudent();
    cout << Cstudent::gettotal() << " " << stu[0].getactualtotal() << endl;//两种访问静态方法

    Cstudent *pa = new Cstudent("wang");
    pa->showstudent();
    delete pa;

    Cstudent *pb;
    pb = new Cstudent[10];
    for(int i=0;i<10;i++)
        pb[i].showstudent();
    delete[]pb;

    return 0;
}