42 lines
1.1 KiB
C++
42 lines
1.1 KiB
C++
/* 运算符重载之强制转换.cpp */
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/*
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有一个类Circle，设计该类的类型转换函数，当将Circle对象转换成int型时，返回圆的半径；当将它转换成double型时，就返回圆的周长；当将它转换成float型时，就返回圆的面积。
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*/
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/*
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类型转换函数没有参数。
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类型转换函数没有返回类型。
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类型转换函数必须返回将要转换成的type类型数据。
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*/
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#include <iostream>
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using namespace std;
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class Circle {
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private:
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double x, y, r;
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public:
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Circle(double x1, double y1, double r1) {
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x = x1;
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y = y1;
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r = r1;
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}
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operator int() { return int(r); }
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operator double() { return 2 * 3.14 * r; }
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operator float() { return (float)3.14 * r * r; }
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};
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int main() {
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Circle c(2.3, 3.4, 2.5);
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int r = c; //调用operator int()，将Circle类型转换成int
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double length = c; //调用operator double()，转换成double
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float area = c; //调用operator float()，将Circle类型转换成float
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double len = (double)c; //将Cirlce类型对象强制转换成double
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cout << r << endl;
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cout << length << endl;
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cout << len << endl;
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cout << area << endl;
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}
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