93 lines
1.9 KiB
C++
93 lines
1.9 KiB
C++
// 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。
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// 【提示】全局函数排序函数 void sort(Shape *arr, int size)
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#include <iostream>
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#include <cstring>
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#include <cstdlib>
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using namespace std;
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class Shape
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{
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public:
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// 用于计算形状的周长
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virtual double perimeter() = 0;
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};
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class Triangle : public Shape
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{
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private:
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double a, b, c;
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public:
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Triangle(double a, double b, double c) : a(a), b(b), c(c) {}
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public:
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double perimeter()
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{
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return a + b + c;
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}
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};
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class Square : public Shape
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{
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private:
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double a;
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public:
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Square(double a) : a(a) {}
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public:
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double perimeter()
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{
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return 4 * a;
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}
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};
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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
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{
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for (int i = 0; i < size - 1; i++)
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{
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for (int j = 0; j < size - i - 1; j++)
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{
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// 比较形状的周长
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if (arr[j]->perimeter() < arr[j + 1]->perimeter())
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{
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// 交换位置
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swap(arr[j], arr[j + 1]);
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}
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}
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}
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}
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int main()
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{
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Shape *p = new Triangle(3, 4, 5);
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Shape *q = new Square(5);
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Shape *r = new Triangle(6, 8, 10);
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Shape *s = new Square(10);
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Shape *t = new Triangle(5, 12, 13);
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Shape *u = new Square(13);
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// Shape *arr[6];
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// arr[0] = p;
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// arr[1] = q;
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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
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int len = sizeof(arr) / sizeof(arr[0]);
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cout << "排序前：" << endl;
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for (int i = 0; i < len; i++)
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{
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cout << arr[i]->perimeter() << endl;
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}
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sort(arr, len);
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cout << "排序后：" << endl;
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for (int i = 0; i < len; i++)
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{
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cout << arr[i]->perimeter() << endl;
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}
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return 0;
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}
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