Add schooling_v1.cpp

schooling_v1.cpp

@@ -0,0 +1,75 @@
+#include <iostream>
+#include <string>
+
+using std::string, std::cout, std::cin, std::endl;
+
+class Student
+{
+protected:
+    string name;
+    int age;
+
+public:
+    Student(string _name, int _age) : name{_name}, age{_age} {}
+    int schooling()
+    {
+        return 0; // 空泛的学生类，缺乏收费依据，直接返回0
+    }
+};
+
+class MiddleStudent : public Student
+{
+    int books;
+
+public:
+    MiddleStudent(string _name, int _age, int _books)
+        : Student(_name, _age), books{_books} {}
+    int schooling()
+    {
+        return books * 20; // 中学生按20元单价收书本费
+    }
+};
+
+class CollegeStudent : public Student
+{
+    int credit;
+
+public:
+    CollegeStudent(string _name, int _age, int _credit)
+        : Student(_name, _age), credit{_credit} {}
+    int schooling()
+    {
+        return credit * 120; // 大学生按120单价收学分费
+    }
+};
+
+class GraduateStudent : public Student
+{
+    int credit;
+
+public:
+    GraduateStudent(string _name, int _age, int _credit)
+        : Student(_name, _age), credit{_credit} {}
+    int schooling()
+    {
+        return credit * 200; // 研究生按200单价收学分费
+    }
+};
+
+int get_total(Student s[], int len)
+{
+    int total{};
+    for (int i{0}; i < len; ++i)
+        total += s[i].schooling();
+    return total;
+}
+
+int main()
+{
+    MiddleStudent ms{"张三", 15, 20};
+    CollegeStudent cs{"张二", 18, 150};
+    GraduateStudent gs{"张大", 22, 40};
+    Student s[]{ms, cs, gs};
+    std::cout << get_total(s, 3) << '\n';
+    // 本程序失败了，输出为0，为什么？
+}