Question

c++.定义一个Circle类，包括数据成员R（半径），成员函数Area（）,计算圆的面积，定义一个对象C进行测试

Answer 1

//Circle.h
#pragma once
#define PI 3.14159

class Circle
{
public:
Circle(double r);
~Circle();

double Area();

public:
double R;
};

//Circle.cpp
#include "Circle.h"

Circle::Circle(double r)
{
R = r;
}

Circle::~Circle(void)
{
}

double Circle::Area()
{
return PI*R*R;
}

//main.cpp
#include <iostream>
#include "Circle.h"

using namespace std;

int main()
{
Circle cir(3.5);

cout<<cir.Area()<<endl;

getchar();
return 0;
}