Question

用C++做一个【求圆柱体积】小程序：

在主函数中编写代码，让用户输入圆柱的半径和高度，如果输入的数据合理，计算圆柱体积并打印结果，【重点】：如果输入数据不合理，提示用户重新输入，用户有三次输入机会。

Answer 1

以下代码包括了球、圆柱和圆锥的表面积和体积的计算，做一下修改即可源程序与注释：#include "iostream.h" //库函数#include “math.h”class Circle //基类圆 { public: //公共成员double r; public: void print() //输出圆的半径 { cout<<"半径为:"<<r<<endl; } Circle(double x)//圆的构造函数 { r=x; } double GetR()//获取圆的半径 { return r; //返回圆的半径 } }; class Sphere:public Circle//球类 { public: //公共成员Sphere(double x):Circle(x)//球的构造函数 { } double GetTheSphereArea()//获取球的表面积 { double R=GetR(); return (4*3.14*R*R); //球的表面积公式} double GetTheSphereVolume()//获取球的体积 { double R=GetR(); return ((3.14*R*R*R)*4/3); //球的体积公式} }; class Cylinder:public Circle//圆柱类 { public: double h; Cylinder(double x ,double y):Circle(x)//圆柱类的构造函数 { h=y; } double GetTheCylinderArea()//获圆柱类的表面积 { double R=GetR(); return (2*3.14*R*R+2*3.14*R*h); //圆柱表面积公式} double GetTheCylinderVolume()//获圆柱类的体积 { double R=GetR(); return (3.14*R*R*h); //圆柱体积公式} }; class Vec:public Circle//圆锥类 { public: double h; Vec(double x ,double y):Circle(x)//圆锥类的构造函数 { h=y; } double GetTheVecArea()//获圆锥类的表面积 { double R=GetR(); return (3.14*R*R+3.14*R*sqrt(R*R+h*h));//表面积 S=π*r^2+πrl (l为母线长） } double GetTheVecVolume()//获圆锥类的体积 { double R=GetR(); return (3.14*R*R*h)/3; } }; void main()//主函数 { Sphere Sphere1(2.5);//初始球类对象 double a=Sphere1.GetTheSphereArea(); //获取球的表面积cout<<"(1)球的表面积为"<<a<<endl; a=Sphere1.GetTheSphereVolume(); //获取球的体积cout<<" 球的体积为"<<a<<endl; Cylinder Cylinder1(2,3);//初始圆柱类对象double b=Cylinder1.GetTheCylinderArea(); //圆柱的表面积cout<<"(2)圆柱的表面积为"<<b<<endl; b=Cylinder1.GetTheCylinderVolume(); //圆柱的体积cout<<" 圆柱的体积为"<<b<<endl; Vec Vec1(2，3);//初始圆锥类对象double c=Vec1.GetTheVecArea(); //圆锥的表面积cout<<"(3)圆锥的表面积为"<<c<<endl; c=Vec1.GetTheVecVolume(); //圆锥的体积cout<<" 圆锥的体积为"<<c<<endl; }

Answer 2

#include <cstdio>
int main() {
    double radius = -1.0, height = -1.0;
    while(radius <= 0.0) {
        printf("请输入圆柱体的半径");
        scanf("%lf",&radius);
    }
    while(height <= 0.0) {
        printf("请输入圆柱体的高度");
        scanf("%lf",&height);
    }
    printf("你输入的圆柱体 半径 %lf, 高度 %lf, 体积为 %lf\n", radius, height, PI*radius*radius*height);
    return 0;
}

Answer 3

#include <iostream>
#define PI 3.1415926
using namespace std;int main(void)
{
float a,b;
int i = 0;
while (i < 3)
{
i++;
cout<<"输入半径";
cin>>a;
cout<<"输入高度:";
cin>>b;
if (a>0 && b>0)
break;
else
{
if (i>=3)
exit(1);
cout<<"数据有误，请重新输入"<<endl;
}
}
cout<<"体积:"<<PI*a*a*b<<endl;
return 0;
}

Answer 4

这次应该ok了，可以处理输入非数字的情况，刚才的代码还有点问题

#include <iostream>
using namespace std;

int main()
{
int n = 4;
double r, h, v;
while(--n) {
cout << "请输入圆柱的半径和高:";
cin >> r >> h;
if(cin.fail() || r <= 0 || h <= 0) {
cout << "数据输入不合理，请重新输入！\n";
cin.clear();
cin.ignore(1024, '\n');
} else break;
cout << "你还有 " << n-1 << " 次重试机会。\n";
}
if(n != 0) {
v = 3.14 * r*r * h;
cout << "\n圆柱的体积是:" << v << endl;
} else {
cout << "\n机会用完，程序结束。\n";
}
}

Answer 5

#include <iostream>
using namespace std;
const PI = 3.1415926;class Cylinder
{
public:
void SetCylinderValue();
void OutputCylinder();
BOOL Check();
private:
double r;
double h;
};void Cylinder::SetCylinderValue()
{
double sr,sh;
cout<<"Please input cylinder's information:"<<endl;
cout<<"r = ";
cin>>sr;
cout<<"h = ";
cin>>sh;
r = sr;
h = sh;
}BOOL Cylinder::Check()
{
if(r <= 0 || h <= 0)
{
cout<<"Error!Please check the data!"<<endl;
return FALSE;
}
else
return TRUE;
}void Cylinder::OutputCylinder()
{
cout<<"Result : "<<PI * r * r * h<<endl;
}int main()
{
Cylinder cylinder;
int i = 0;
while(i != 3)
{
cylinder.SetCylinderValue();
if(!cylinder.Check())
{
i++;
continue;
}
else
{
cylinder.OutputCylinder();
break;
}
}
if(i == 3)
cout<<"You have no chance to continue!"<<endl;
}