44 lines
777 B
C++
44 lines
777 B
C++
/* 抽象类.cpp */
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#include <iostream>
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using namespace std;
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class Figure {
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protected:
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double x, y;
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public:
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void set(double i, double j) {
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x = i;
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y = j;
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}
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virtual void area() = 0;
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};
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class Trianle : public Figure {
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public:
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void area() { cout << "三角形面积：" << x * y * 0.5 << endl; }
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};
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class Rectangle : public Figure {
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public:
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void area() { cout << "这是矩形，它的面积是：" << x * y << endl; }
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};
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int main(int argc, char const *argv[]) {
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//定义抽象类指针
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Figure *pF = NULL;
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// Figure f1; 抽象类不能被实例化
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Rectangle r;
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Trianle t;
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t.set(10, 20);
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pF = &t;
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pF->area();
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r.set(10, 20);
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pF = &r;
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pF->area();
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//定义抽象类引用
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Figure &rF = t;
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rF.set(20, 20);
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rF.area();
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return 0;
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}
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