day6: homework

day6/homework/h1.cpp

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+// 编写一个模板函数 maxValue，接受两个参数，并返回其中较大的值。
+// 【提示】T maxVal(T &v1, T &v2)
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+
+using namespace std;
+
+template <typename T>
+T maxVal(T &v1, T &v2)
+{
+    return v1 > v2 ? v1 : v2;
+}
+
+int main()
+{
+    int a = 2, b = 5;
+    cout << "更大的值是: " << maxVal(a, b) << endl;
+    return 0;
+}

day6/homework/h2.cpp

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+// 编写一个模板函数 maxValueInArray，接受一个数组和数组的大小，并返回数组中的最大值。
+//【提示】T maxValueInArray(T arr[], int size)
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+
+using namespace std;
+
+template <typename T>
+T maxValueInArray(T arr[], int size)
+{
+    T max = arr[0];
+    for (int i = 1; i < size; i++)
+        if (arr[i] > max)
+            max = arr[i];
+    return max;
+}
+
+int main()
+{
+    int arr1[] = {1, 3, 5, 7, 9, 2, 4, 6, 8, 0};
+    char arr2[] = {'a', 'c', 'e', 'G', 'I', 'b', 'd', 'f', 'h', 'j'};
+    int size1 = sizeof(arr1) / sizeof(arr1[0]);
+    int size2 = sizeof(arr2) / sizeof(arr2[0]);
+
+    cout << "arr1 的最大值是: " << maxValueInArray(arr1, size1) << endl;
+    cout << "arr2 的最大值是: " << maxValueInArray(arr2, size2) << endl;
+    return 0;
+}

day6/homework/h3.cpp

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+// 创建一个基类 Person，其中包含一个纯虚函数 display() ，用于显示人的信息。从 Person 派生出 Student 类和 Teacher 类，分别实现不同类型人的信息显示。
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+
+using namespace std;
+
+class Person
+{
+public:
+    virtual void display() = 0;
+};
+
+class Student : public Person
+{
+public:
+    // 子类的 virtual 函数可以不写 virtual 关键字
+    virtual void display()
+    {
+        cout << "Student" << endl;
+    }
+};
+
+class Teacher : public Person
+{
+public:
+    virtual void display()
+    {
+        cout << "Teacher" << endl;
+    }
+};
+
+int main()
+{
+    Person *p = new Student();
+    p->display();
+    p = new Teacher();
+    p->display();
+    return 0;
+}

day6/homework/h4.cpp

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+// 创建一个基类 Animal，其中包含一个纯虚函数 move() ，用于描述动物的移动方式。从 Animal 派生出 Bird 类和 Fish 类，分别实现不同类型动物的移动方式。
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+
+using namespace std;
+
+class Animal
+{
+public:
+    virtual void move() = 0;
+};
+
+class Bird : public Animal
+{
+public:
+    void move()
+    {
+        cout << "Bird" << endl;
+    }
+};
+
+class Fish : public Animal
+{
+public:
+    void move()
+    {
+        cout << "Fish" << endl;
+    }
+};
+
+int main()
+{
+    Animal *p = new Bird;
+    p->move();
+    p = new Fish;
+    p->move();
+    return 0;
+}

day6/homework/h5.cpp

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+// 创建一个基类 Shape，其中包含一个纯虚函数 draw() ，用于绘制形状。从 Shape 派生出 Rectangle 类和 Circle 类，分别实现不同形状的绘制方法
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+
+using namespace std;
+
+class Shape
+{
+public:
+    virtual void draw() = 0;
+};
+
+class Rectangle : public Shape
+{
+public:
+    void draw()
+    {
+        cout << "Rectangle" << endl;
+    }
+};
+
+class Circle : public Shape
+{
+public:
+    void draw()
+    {
+        cout << "Circle" << endl;
+    }
+};
+
+int main()
+{
+    Shape *p = new Rectangle;
+    p->draw();
+    p = new Circle;
+    p->draw();
+    return 0;
+}

day6/homework/h6.cpp

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+// 创建一个基类 Shape，其中包含一个纯虚函数 perimeter() ，用于计算形状的周长。从 Shape 派生出 Triangle 类和 Square 类，分别实现计算三角形和正方形的周长的函数。
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+
+using namespace std;
+
+class Shape
+{
+public:
+    // 用于计算形状的周长
+    virtual double perimeter() = 0;
+};
+
+class Triangle : public Shape
+{
+private:
+    double a, b, c;
+
+public:
+    Triangle(double a, double b, double c) : a(a), b(b), c(c) {}
+
+public:
+    double perimeter()
+    {
+        return a + b + c;
+    }
+};
+
+class Square : public Shape
+{
+private:
+    double a;
+
+public:
+    Square(double a) : a(a) {}
+
+public:
+    double perimeter()
+    {
+        return 4 * a;
+    }
+};
+
+int main()
+{
+    Shape *p = new Triangle(3, 4, 5);
+
+    cout << "三角形的周长是: " << p->perimeter() << endl;
+
+    p = new Square(5);
+
+    cout << "正方形的周长是: " << p->perimeter() << endl;
+    return 0;
+}

day6/homework/h7.cpp

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+// 继第6题， 基于多态方式，定义一个全局函数排序函数，接收Shape类的数组，并按形状的周长进行从大到少排序。
+// 【提示】全局函数排序函数 void sort(Shape *arr, int size)
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+
+using namespace std;
+
+class Shape
+{
+public:
+    // 用于计算形状的周长
+    virtual double perimeter() = 0;
+};
+
+class Triangle : public Shape
+{
+private:
+    double a, b, c;
+
+public:
+    Triangle(double a, double b, double c) : a(a), b(b), c(c) {}
+
+public:
+    double perimeter()
+    {
+        return a + b + c;
+    }
+};
+
+class Square : public Shape
+{
+private:
+    double a;
+
+public:
+    Square(double a) : a(a) {}
+
+public:
+    double perimeter()
+    {
+        return 4 * a;
+    }
+};
+
+void sort(Shape *arr[], int size) // 这里为什么传指针数组？因为 Shape 是抽象类，不能实例化对象，只能通过指针来操作
+{
+    for (int i = 0; i < size - 1; i++)
+    {
+        for (int j = 0; j < size - i - 1; j++)
+        {
+            // 比较形状的周长
+            if (arr[j]->perimeter() < arr[j + 1]->perimeter())
+            {
+                // 交换位置
+                swap(arr[j], arr[j + 1]);
+            }
+        }
+    }
+}
+
+int main()
+{
+    Shape *p = new Triangle(3, 4, 5);
+    Shape *q = new Square(5);
+    Shape *r = new Triangle(6, 8, 10);
+    Shape *s = new Square(10);
+    Shape *t = new Triangle(5, 12, 13);
+    Shape *u = new Square(13);
+    // Shape *arr[6];
+    // arr[0] = p;
+    // arr[1] = q;
+    Shape *arr[] = {p, q, r, s, t, u}; // arr作为一个指针数组，存了6个指向 Shape 类对象的指针
+    int len = sizeof(arr) / sizeof(arr[0]);
+
+    cout << "排序前：" << endl;
+
+    for (int i = 0; i < len; i++)
+    {
+        cout << arr[i]->perimeter() << endl;
+    }
+
+    sort(arr, len);
+
+    cout << "排序后：" << endl;
+    for (int i = 0; i < len; i++)
+    {
+        cout << arr[i]->perimeter() << endl;
+    }
+
+    return 0;
+}