I'm trying to write a program that will compute the volume and surface area of
a sphere, cylinder, and a circular cone using function and array. I'm a beginner in C++. I need serious help. I'm struggling with the looping part. I try many syntax without success. I spent already 3 days on it. anything that will guide me in the right direction will be greatly appreciate.
example of the output:
Select a Shape (1) sphere (2) cylinder (3) cone (q) quit: 1
Select a Computation (1) volume (2) surface area: 1
Enter radius of sphere: 5.5
Volume of sphere is 696.91
Select a Shape (1) sphere (2) cylinder (3) cone (q) quit: 1
Select a Computation (1) volume (2) surface area: 2
Enter radius of sphere: 5.5
Surface area of sphere is 380.133
Select a Shape (1) sphere (2) cylinder (3) cone (q) quit: 2
Select a Computation (1) volume (2) surface area: 1
Enter radius of cylinder: 5.5
Enter height of cylinder: 4.2
Volume of cylinder is 399.139
Select a Shape (1) sphere (2) cylinder (3) cone (q) quit: 2
Select a Computation (1) volume (2) surface area: 2
Enter radius of cylinder: 5.5
Enter height of cylinder: 4.2
Surface area of cylinder is 335.208
Select a Shape (1) sphere (2) cylinder (3) cone (q) quit: 3
Select a Computation (1) volume (2) surface area: 1
Enter radius of cone: 5.5
Enter height of cone: 4.2
Volume of cone is 133.046
Select a Shape (1) sphere (2) cylinder (3) cone (q) quit: 3
Select a Computation (1) volume (2) surface area: 2
Enter radius of cone: 5.5
Enter height of cone: 4.2
Surface area of cone is 214.607
Select a Shape (1) sphere (2) cylinder (3) cone (q) quit: q
Good bye!
here are my codes:
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#include<iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath> //math library function
using namespace std;
const double PI = 3.14159; //constant variable for PI
//prototype functions
double sphere_Volume(double radius);
double cylinder_volume(double radius, double height);
double cone_volume(double radius, double height);
double sphere_surface_area(double radius);
double cylinder_surface_area(double radius, double height);
double cone_surface_area(double radius, double height);
int main( )
{
//declare variables
double radius;
double height;
char select = 'q';
const int SHAPES = 3; // length of array for the shapes (sphere, cylinder, cone)
string shape[SHAPES]; //array of strings, size 3
int input = 1; // store user inputs for the shapes
shape[0] = "sphere"; // arrays from zero to 2
shape[1] = "cylinder";
shape[2] = "cone";
const int COMPUTATION = 2; //length of array for the computation (volume, surfacearea)
string comp[COMPUTATION]; //array of strings, size 2
int inputcomp = 1; //store user inputs for the computation
comp[0] = "radius"; //arrays from zero to 1
comp[1] = "height";
// while (select != 'q') if 'q' is not select keep on running
//{ my problem is here
while(input < 1  input > 3) //make sure user enter number between 1 and 3
{
//prompt user to select a shape
cout << "select a shape (1)sphere, (2) cylinder, (3) cone, (q) to quit: ";
cin >> input;
}
while (inputcomp < 1  inputcomp > 2)//make sure user enter number between 1 and 2
{
//prompt user to select a computation
cout << "Select a computation (1) volume, (2) surface area: ";
cin >> inputcomp;
}
if (input == 1 && inputcomp == 1) //if sphere and volume is select
{
cout << "Enter radius of sphere: "; //prompt user to enter radius
cin >> radius;
//call the function to display the sphere's volume
cout << "Volume of the sphere is: " << sphere_Volume(radius) << endl;
}
else if (input == 2 && inputcomp == 1) //if cylinder and volume is select
{
cout << "Enter radius of cylinder: "; //prompt user to enter radius
cin >> radius;
cout << "Enter height of cylinder: "; //prompt user to enter height
cin >> height;
//call the function to display the cylinder's volume
cout << "Volume of the cylinder is: " << cylinder_volume(radius, height) << endl;
}
else if (input == 3 && inputcomp == 1) //if cone and volume is select
{
cout << "Enter radius of cone: ";//prompt user to enter radius
cin >> radius;
cout << "Enter height of cone: ";//prompt user to enter height
cin >> height;
//call the function to display the cone's volume
cout << "Volume of the cone is: " << cone_volume(radius, height) << endl;
}
else if (input == 1 && inputcomp == 2)//if sphere and surfacearea is select
{
cout << "Enter radius of sphere: ";//prompt user to enter radius
cin >> radius;
//call the function to display the sphere's surfacearea
cout << "surfacearea of the sphere is: " << sphere_surface_area(radius) << endl;
}
else if (input == 2 && inputcomp == 2)//if cylinder and surfacearea is select
{
cout << "Enter radius of cylinder: ";//prompt user to enter radius
cin >> radius;
cout << "Enter height of cylinder: ";//prompt user to enter height
cin >> height;
//call the function to display the cylinder's surfacearea
cout << "surfacearea of the cylinder is: " << cylinder_surface_area(radius, height) << endl;
}
else if (input == 3 && inputcomp == 2)//if cone and surfacearea is select
{
cout << "Enter radius of cone: ";//prompt user to enter radius
cin >> radius;
cout << "Enter height of cone: ";//prompt user to enter height
cin >> height;
//call the function to display the cone's surfacearea
cout << "surfacearea of the cone is: " << cone_surface_area(radius, height) << endl;
}
//}
system("pause");
return 0;
} // end main function
double sphere_Volume(double radius)
{
return 4.0 / 3.0 * PI * pow( radius, 3 );
}
double cylinder_volume(double radius, double height)
{
return PI * pow(radius, 2) * height;
}
double cone_volume(double radius, double height)
{
return 1.0 / 3.0 * PI * pow(radius, 2) * height;
}
double sphere_surface_area(double radius)
{
return 4.0 * PI * pow(radius, 2);
}
double cylinder_surface_area(double radius, double height)
{
return (2.0 * PI * pow(radius, 2)) + (2.0 * PI * radius * height);
}
double cone_surface_area(double radius, double height)
{
return (PI * pow(radius, 2)) + (PI * radius * sqrt(pow(radius, 2) + pow(height, 2)));
}
 