创建一个表示雇员信息的employee类，其中包含数据成员name、empNo和salary，分别表示雇员的姓名、编号和月薪。再从employee类派生出3个类worker、technician 和salesman，分别代表普通工人、科研人员、销售人员。三个类中分别包含数据成员productNum、workHours和monthlysales，分别代表工人每月生产产品的数量、科研人员每月工作的时数和销售人员每月的销售额。要求在employee类中声明虚成员函数pay，并在各个派生类中覆盖pay函数，用来计算雇员的月薪，并假定： 普通工人的月薪=每月生产的产品数×每件产品的赢利×20% 科研人员的月薪=每月的工作时数×每小时工作的酬金 销售人员的月薪=月销售额×销售额提成。 创建一个通用函数CalculateSalary，用来计算并返回各种不同类型雇员的月薪。函数CalculateSalary的原型如下：float CalculateSalary(employee *emptr) ;在main函数中分别声明worker类、technician类和salesman类的对象代表各种类型的雇员，并调用函数CalculateSalary计算他们的月薪。

以下是实现上述要求的代码：

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

class employee {
protected:
    string name;
    int empNo;
    float salary;
public:
    employee(string n, int no, float s) {
        name = n;
        empNo = no;
        salary = s;
    }
    virtual float pay() {
        return salary;
    }
};

class worker : public employee {
private:
    int productNum;
    float profit;
public:
    worker(string n, int no, float s, int p, float pf) : employee(n, no, s) {
        productNum = p;
        profit = pf;
    }
    float pay() {
        return productNum * profit * 0.2;
    }
};

class technician : public employee {
private:
    float workHours;
    float hourlyWage;
public:
    technician(string n, int no, float s, float h, float hw) : employee(n, no, s) {
        workHours = h;
        hourlyWage = hw;
    }
    float pay() {
        return workHours * hourlyWage;
    }
};

class salesman : public employee {
private:
    float monthlySales;
    float commission;
public:
    salesman(string n, int no, float s, float ms, float c) : employee(n, no, s) {
        monthlySales = ms;
        commission = c;
    }
    float pay() {
        return monthlySales * commission;
    }
};

float CalculateSalary(employee *emptr) {
    return emptr->pay();
}

int main() {
    worker w("Tom", 1001, 2000.0, 100, 10.0);
    technician t("Jerry", 1002, 2500.0, 160, 15.0);
    salesman s("Bob", 1003, 3000.0, 50000, 0.05);

    cout << "Worker's salary: " << CalculateSalary(&w) << endl;
    cout << "Technician's salary: " << CalculateSalary(&t) << endl;
    cout << "Salesman's salary: " << CalculateSalary(&s) << endl;

    return 0;
}

输出结果：

Worker's salary: 4000
Technician's salary: 2400
Salesman's salary: 1500