// Sizing a pond for happy fish

import <iostream>;

import <numbers>; // For the pi constant

#include <cmath> // For the square root function

int main()

{

// 2 square feet pond surface for every 6 inches of fish

const double fish_factor { 2.0/0.5 }; // Area per unit length of fish

const double inches_per_foot { 12.0 };

double fish_count {}; // Number of fish

double fish_length {}; // Average length of fish

std::cout << "Enter the number of fish you want to keep: ";

std::cin >> fish_count;

std::cout << "Enter the average fish length in inches: ";

std::cin >> fish_length;

fish_length /= inches_per_foot; // Convert to feet

std::cout << '\n';

// Calculate the required surface area

const double pond_area {fish_count * fish_length * fish_factor};

// Calculate the pond diameter from the area

const double pond_diameter {2.0 * std::sqrt(pond_area / std::numbers::pi)};

std::cout << "Pond diameter required for " << fish_count << " fish is "

<< pond_diameter << " feet.\n";

}