# C++ Code Example: volume and surface area of a ball

The code calculates the volume and surface area of a sphere. The sphere is defined by its radius `r` which is entered by the user. The code consists of three parts:

1. `getVolume` function: This function calculates the volume of the sphere. The volume of a sphere is given by `(4 * pi * r^3) / 3`. In the function, `pow(base, exponent)` is used to calculate `r^3`. The constant `M_PI` is defined in `<math.h>` library and it is used to represent the value of pi.
2. `getSurfaceArea` function: This function calculates the surface area of the sphere. The surface area of a sphere is given by `4 * pi * r^2`. In the function, `pow(base, exponent)` is used to calculate `r^2`.
3. Main function: This function is the starting point of the code. It first prompts the user to enter the value of the radius `r`. Then, it calls the `getVolume` and `getSurfaceArea` functions to calculate the volume and surface area of the sphere, respectively. Finally, it rounds the values of volume and surface area and outputs them.

Note: The `round` function is used to round the values of volume and surface area to the nearest integer.

``````#include &lt;iostream&gt;
#include &lt;math.h&gt;
using namespace std;

double getVolume(double r) {
// Math.pow(base, exponent): Returns base raised to the power exponent
return (4 * M_PI * pow(r, 3)) / 3;
}

double getSurfaceArea(double r) {
return 4 * M_PI * pow(r, 2);
}

int main(){
double r, area, volume;

cin >> r;

area = getSurfaceArea(r);
volume = getVolume(r);

cout << "Volume: " << round(volume) << endl;
cout << "Surface Area: " << round(area);

return 0;
}``````
##### Output
``````Please enter radius: 2
Volume: 34
Surface Area: 50``````