Question

#include<stdio.h>
#include<iostream>
using namespace std;
class Calculate   //class form
{
  int r,h ;

public:
    void getdata()  //input data
    {
        cout<<"Enter the radius and height";
        cin>>r>>h;

    }
    void  Surfacearea()
    {
            float a;
            a= ( ( 2 * 3.14 * r * r ) + ( 2 * 3.14 * r * h ) );
            cout<<"the sa of cylinder is"<<a;
        }
    void volume()
    {
        float v;
        v = ( 3.14 * r * r * h );
     cout<<"the volume of cylinder is"<<v;
}

};
Calculate a1,a2,g; 
int main()
{
g.getdata();    
a1.Surfacearea();
a2.volume();

}

我得到surfacearea和音量为零，我无法在代码中找到错误，请帮助我.......................... .................................................. ..............................................

Answer 1

你的课程计算没问题。

问题出在函数main中，当你调用g.getdata（）时，你正在读变量'h'和amp;对象'g'的'r'，然后你调用a1.SurfaceArea（）和a2.volume（）试图显示结果，但你从未调用过对象a1和a2 !!的函数getdata。因此'r'和'h'未被初始化为a1和a2。

所以只需在调用函数SurfaceArea和volume之前添加它，它应该可以工作：

a1.getdata();
a2.getdata();

Answer 2

您可能想要考虑您的课程设计。以下是我的写作方式：

#include <iostream>
#include <stdio.h>

#define _USE_MATH_DEFINES
#include <math.h>

using namespace std;

class Cylinder
{
public:

    Cylinder() : 
        m_radius(0.0),
        m_height(0.0)
    {
    }

    void SetHeight(double height)
    {
        m_height = height;
    }

    void SetRadius(double radius)
    {
        m_radius = radius;
    }

    double GetSurfaceArea() const
    {
        double area = (2.0 * M_PI * m_radius * m_radius) + (2.0 * M_PI * m_radius * m_height);
        return area;
    }

    double GetVolume() const
    {
        double volume = (M_PI * m_radius * m_radius * m_height);
        return volume;
    }

private:
    double m_radius;
    double m_height;
};


int main()
{
    double radius = 0.0;
    double height = 0.0;

    cout << "Enter the radius and height";
    cin >> radius >> height;

    Cylinder cylinder;
    cylinder.SetHeight(height);
    cylinder.SetRadius(radius);

    cout << "the sa of cylinder is: " << cylinder.GetSurfaceArea() << endl;
    cout << "the volume of cylinder is: " << cylinder.GetVolume() << endl;

    return 0;
}

C ++程序，使用两个独立的函数计算圆柱体的表面积和体积

2 个答案: