13年题。

OOP/13Exam/2.1.cpp

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+// 在下面基类Base和派生类Derived中增加成员函数show，使得程序运行结果如下：
+// Base
+// Derived
+
+#include <iostream>
+using namespace std;
+class Base {
+public:
+    // _________________________;
+
+    virtual void show() {
+        cout << "Base" << endl;
+    }
+};
+
+class Derived : public Base {
+public:
+    // __________________________;
+
+    virtual void show() {
+        cout << "Derived" << endl;
+    }
+};
+
+int main() {
+    Base b, *ptr;
+    Derived d;
+    ptr = &b;
+    ptr->show();
+    ptr = &d;
+    ptr->show();
+    return 0;
+};

OOP/13Exam/2.2.cpp

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+// 以下程序是定义一个计数器类counter，对其重载运算符“+”。请编写运算符重载函数，使得程序输出结果如下：
+//  n = 5
+//  n = 10
+//  n = 15
+
+#include <iostream>
+using namespace std;
+class counter {
+private:
+    int n;
+
+public:
+    counter() {
+        n = 0;
+    }
+    counter(int i) {
+        n = i;
+    }
+
+    //_____________________
+    //    {_____________________}
+
+    counter operator+(const counter &otherCounter) {
+        return counter(this->n + otherCounter.n);
+    }
+
+    void disp() {
+        cout << "n=" << n << endl;
+    }
+};
+
+int main() {
+    counter c1(5), c2(10), c3;
+    c3 = c1 + c2;
+    c1.disp();
+    c2.disp();
+    c3.disp();
+    return 0;
+}

OOP/13Exam/2.3.cpp

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+// 在给出的时间类Time中，增加show_time函数，以时：分：秒的格式显示时间。
+
+#include <iostream>
+using namespace std;
+class Time {
+public:
+    Time(int h, int m, int s) {
+        hour = h, minute = m, sec = s;
+    }
+
+    // ______________________
+    //     {_______________________}
+
+    void show_time() {
+        cout << hour << ":" << minute << ":" << sec << endl;
+    }
+
+private:
+    int hour, minute, sec;
+};
+
+int main() {
+    Time T(5, 0, 0);
+    T.show_time();
+    return 0;
+}

OOP/13Exam/2.4.cpp

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+// 已知文件test.txt的内容如下：
+// Good Morning!
+// Good Night!
+// Good Luck!
+// 补充下面程序，使得输出结果如下：
+// 1:Good Morning!
+// 2:Good Night!
+// 3:Good Luck!
+
+#include <iostream>
+#include <fstream>
+using namespace std;
+const int size = 100;
+int main() {
+    char buf[::size];
+    // _______________
+
+    ifstream in("test.txt", ios::in);
+
+    int i = 1;
+    while (in.getline(buf, ::size)) {
+        // ____________________
+
+        cout << i <<":" << buf << endl;
+        i++;
+    }
+}

OOP/13Exam/2.5.cpp

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+// 下面定义了一个shape抽象类，派生出Rectangle类，用于计算Rectangle类对象的面积Area()。请补充完整下面的程序，使程序输出60。
+
+#include <cstring>
+#include <iostream>
+using namespace std;
+class Shape {
+public:
+    // _________________
+
+    virtual void Area() = 0;
+};
+
+class Rectangle : public Shape {
+public:
+    // _________________
+
+    int width, height;
+
+    Rectangle(int _width, int _height) : width(_width), height(_height) {
+    }
+
+    void Area() {
+        cout << width * height << endl;
+    }
+};
+
+int main() {
+    Shape *sp;
+    Rectangle re1(10, 6);
+    sp = &re1;
+    sp->Area();
+    return 0;
+}

OOP/13Exam/3.1.cpp

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+#include <iostream>
+using namespace std;
+
+class test {
+private:
+    int num;
+    float fl;
+
+public:
+    test();
+    int getint() {
+        return num;
+    }
+    float getfloat() {
+        return fl;
+    }
+    ~test();
+};
+
+test::test() {
+    cout << "Initializing default" << endl;
+    num = 0;
+    fl = 0.0;
+}
+
+test::~test() {
+    cout << "Destructor is active" << endl;
+}
+
+int main() {
+    test array[2];
+    cout << array[1].getint() << "" << array[1].getfloat() << endl;
+    return 0;
+};
+
+/*
+Initializing default
+Initializing default
+00
+Destructor is active
+Destructor is active
+*/

OOP/13Exam/3.2.cpp

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+#include <iostream>
+using namespace std;
+
+class A {
+    public:
+    A() {
+        cout << "A::A() called.\n";
+    }
+    virtual ~A() {
+        cout << "A::~A() called.\n";
+    }
+};
+
+class B: public A {
+    public:
+    B(int i) {
+        cout << "B::B() called.\n";
+        buf = new char[i];
+    }
+    virtual ~B() {
+        delete [] buf;
+        cout << "B::~B() called.\n";
+    }
+
+    private:
+    char *buf;
+};
+
+void fun(A *a) {
+    delete a;
+}
+
+int main() {
+    A *a = new B(15);
+    fun(a);
+}
+
+/*
+A::A() called.
+B::B() called.
+B::~B() called.
+A::~A() called.
+*/

OOP/13Exam/3.3.cpp

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+#include <iostream>
+using namespace std;
+class Base {
+    private:
+    char c;
+
+    public:
+    Base(char n): c(n) {}
+    virtual ~Base() {
+        cout << c;
+    }
+};
+
+class Der:public Base {
+    private:
+    char c;
+    public:
+    Der(char n):Base(n + 1), c(n) {}
+    ~Der(){
+        cout << c;
+    }
+};
+
+int main() {
+    Der('X');
+    return 0;
+}
+
+/*
+XY
+*/

OOP/13Exam/3.4.cpp

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+#include <iostream>
+using namespace std;
+
+class complex {
+public:
+    complex(double r = 0.0, double i = 0.0) {
+        this->r = r;
+        this->i = i;
+        cout << "Constructor!";
+        display();
+    }
+    complex(complex &c) : r(c.r), i(c.i) {
+        cout << "Copy Constructor!";
+        display();
+    };
+    complex operator+(complex c2);
+    complex operator-(complex c2);
+    void display();
+
+private:
+    double r;
+    double i;
+};
+
+complex complex::operator+(complex c2) {
+    complex result(r + c2.r, i + c2.i);
+    return result;
+}
+
+complex complex::operator-(complex c2) {
+    complex result(r - c2.r, i - c2.i);
+    return result;
+    // return complex(r - c2.r, i - c2.i);
+}
+
+void complex::display() {
+    cout << "(" << r << "," << i << ")" << endl;
+}
+
+int main() {
+    complex c1(5, 4), c2(2, 10), c3;
+    cout << "c1=";
+    c1.display();
+    cout << "c2=";
+    c2.display();
+    c3 = c1 - c2;
+    cout << "c3=c1-c2=";
+    c3.display();
+    c3 = c1 + c2;
+    cout << "c3=c1+c2=";
+    c3.display();
+    return 0;
+}
+
+/*
+
+Constructor!(5,4)
+Constructor!(2,10)
+Constructor!(0,0)
+c1=(5,4)
+c2=(2,10)
+Copy Constructor!(2,10)
+Constructor!(3,-6)
+c3=c1-c2=(3,-6)
+Copy Constructor!(2,10)
+Constructor!(7,14)
+c3=c1+c2=(7,14)
+*/

OOP/13Exam/3.5.cpp

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+#include <iostream>
+#include <string>
+using namespace std;
+class Book {
+    char *title;
+    char *author;
+    int numsold;
+
+public:
+    Book() {
+    }
+    Book(const char *str1, const char *str2, const int num) {
+        int len = strlen(str1);
+        title = new char[len + 1];
+        strcpy(title, str1);
+        len = strlen(str2);
+        author = new char[len + 1];
+        strcpy(author, str2);
+        numsold = num;
+    }
+    void setbook(const char *str1, const char *str2, const int num) {
+        int len = strlen(str1);
+        title = new char[len + 1];
+        strcpy(title, str1);
+        len = strlen(str2);
+        author = new char[len + 1];
+        strcpy(author, str2);
+        numsold = num;
+    }
+    ~Book() {
+        delete title;
+        delete author;
+    }
+    void print(ostream &output) {
+        output << "book:" << title << endl;
+        output << "author:" << author << endl;
+        output << "total:" << numsold << endl;
+    }
+};
+
+int main() {
+    Book obj1("Physics", "LiFu", 200), obj2;
+    obj1.print(cout);
+    obj2.setbook("C++ Programming", "SunJuason", 300);
+    obj2.print(cout);
+    return 0;
+}
+
+/*
+book:Physics
+author:LiFu
+total:200
+book:C++ Programming
+author:SunJuason
+total:300
+*/

OOP/13Exam/test.txt

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+Good Morning!
+Good Night!
+Good Luck!