Volume Shapes Calculator - c++

Question

I was trying out c++ function and recursion but it seems I'm having quite a problem in the variable. I left a comment below where the error usually is found. I dont know where is my problem hoping someone can help me point it out. Thank you! Is it the Variables? or the whole program is flawed? ;-;
#include <conio.h>
#include <iomanip>
#include <iostream>
using namespace std;
float Volume_Cube(float s);
float Volume_Sphere(float r);
float Volume_Rectangle(float w, float h, float l);
int main() {
char opt;
float V;
do {
do {
cout << "*******************************************************" << endl;
cout << " Mark Justine H. Monterde" << endl;
cout << " Volume of Shapes" << endl;
cout << "*******************************************************" << endl;
cout << " [C]-cube" << endl;
cout << " [S]-Sphere" << endl;
cout << " [R]-Rectangular Parallelepiped" << endl;
cout << " [X]-Exit" << endl;
cout << "*******************************************************" << endl;
cin >> opt;
switch (opt) {
case 'C':
case 'c':
float side;
cout << "Enter side: " << endl;
cin >> side;
V = Volume_Cube(side);
cout << fixed << setprecision(2);
cout << "The Volume of the cube is " << V << endl;
break;
case 'S':
case 's':
float radius;
cout << "Enter Radius: " << endl;
cin >> radius;
V = Volume_Sphere(radius);
cout << fixed << setprecision(2);
cout << "The Volume of the Sphere is " << V << endl;
break;
case 'R':
case 'r':
float width, height, length;
cout << "Enter Length: " << endl;
cin >> length;
cout << "Enter Width: " << endl;
cin >> width;
cout << "Enter Height: " << endl;
cin >> height;
V = Volume_Rectangle(width, height, length);
cout << fixed << setprecision(2);
cout << "The Volume of the Rectangular Parallelepiped is " << V
<< endl;
break;
case 'X':
case 'x':
return 0;
break;
default:
cout << "Denied...." << endl;
}
cout << "\nPress any key to continue...\n";
_getch();
} while (opt != 'X ' && opt != 'x');
cout << "\nThank you for using the program \n";
return 0;
}
float Volume_Cube(float s) { //<-mostly my errors comes from here//
float VOLUME;
VOLUME = s * s * s;
return VOLUME;
}
float Volume_Sphere(float r) {
float VOLUME;
const float PI = 3.14;
VOLUME = ((4 / 3) * PI * r * r * r);
return VOLUME;
}
float Volume_Rectangle(float w, float h, float l) {
float VOLUME;
VOLUME = w * h * l;
return VOLUME;
}
}

Answer 1

Here is your code again, with the compiler errors and warnings fixed. It now behaves as [mostly] expected. I placed comments where I made changes and marked them with the text CHANGE: . Your logic was sound, the syntax was just sloppy.
One area that I have not made changes to is how you exit. You immediately return, which means that your code below (thank you message, etc.) is never executed. Making those changes hinders this answer (in my opinion), so I'll leave it pointed out for you to work on. Suggestions are in the comments to this answer as of this writing.
// #include <conio.h> // CHANGE: Removed; outdated and not standard
#include <iomanip>
#include <iostream>
using namespace std;
float Volume_Cube(float s);
float Volume_Sphere(float r);
float Volume_Rectangle(float w, float h, float l);
int main() {
char opt;
float V;
// do { // CHANGE: Removed
do {
cout << "*******************************************************" << endl;
cout << " Mark Justine H. Monterde" << endl;
cout << " Volume of Shapes" << endl;
cout << "*******************************************************" << endl;
cout << " [C]-cube" << endl;
cout << " [S]-Sphere" << endl;
cout << " [R]-Rectangular Parallelepiped" << endl;
cout << " [X]-Exit" << endl;
cout << "*******************************************************" << endl;
cin >> opt;
switch (opt) {
case 'C':
case 'c':
float side;
cout << "Enter side: " << endl;
cin >> side;
V = Volume_Cube(side);
cout << fixed << setprecision(2);
cout << "The Volume of the cube is " << V << endl;
break;
case 'S':
case 's':
float radius;
cout << "Enter Radius: " << endl;
cin >> radius;
V = Volume_Sphere(radius);
cout << fixed << setprecision(2);
cout << "The Volume of the Sphere is " << V << endl;
break;
case 'R':
case 'r':
float width, height, length;
cout << "Enter Length: " << endl;
cin >> length;
cout << "Enter Width: " << endl;
cin >> width;
cout << "Enter Height: " << endl;
cin >> height;
V = Volume_Rectangle(width, height, length);
cout << fixed << setprecision(2);
cout << "The Volume of the Rectangular Parallelepiped is " << V << endl;
break;
case 'X':
case 'x':
return 0;
break;
default:
cout << "Denied...." << endl;
}
cout << "\nPress any key to continue...\n";
// _getch(); // CHANGE: Removed; Not found
} while (opt != 'X' && opt != 'x'); // CHANGE: Extra space after X removed
cout << "\nThank you for using the program \n";
return 0;
}
float Volume_Cube(float s) { //<-mostly my errors comes from here//
float VOLUME;
VOLUME = s * s * s;
return VOLUME;
}
float Volume_Sphere(float r) {
float VOLUME;
const float PI = 3.14;
VOLUME = ((4.0 / 3.0) * PI * r * r * r); // CHANGE: integers to doubles
return VOLUME;
}
float Volume_Rectangle(float w, float h, float l) {
float VOLUME;
VOLUME = w * h * l;
return VOLUME;
}
// } // CHANGE: Removed
Proper formatting, and enabling compiler warnings caught all of these without the need for any actual investigations.
Proper styling can be achieved in many ways. In my case, my editor (VS Code) performs some styling automatically like auto-indents. But I also back that up with a tool, clang-format.
For warnings, -Wall -Wextra should be considered a minimum. Some people might recommend a couple others to go with these, but I consider this a good minimum.

Answer 2

You are declearing functions inside main, that is a function itself, and this is illegal, try declearing them outside.