fish_length = fish_length⼀inches_per_foot； 用鱼的平均长度除以12是什么意思啊？是转换成什么呀？

// Program 2.6 Sizing a pond for happy fish#include <iostream> #include <cmath> // For square root calculationusing std::cout;using std::cin;using std::sqrt;int main() { const double fish_factor = 2.0/0.5; // Area per unit length of fish const double inches_per_foot = 12.0; const double pi = 3.14159265; double fish_count = 0.0; // Number of fish double fish_length = 0.0; // Average length of fish cout << "Enter the number of fish you want to keep: "; cin >> fish_count; cout << "Enter the average fish length in inches: "; cin >> fish_length; fish_length = fish_length/inches_per_foot; // Convert to feet // Calculate the required surface area double pond_area = fish_count * fish_length * fish_factor; // Calculate the pond diameter from the area double pond_diameter = 2.0 * sqrt(pond_area/pi); cout << "尀nPond diameter required for " << fish_count << " fish is " << pond_diameter << " feet.尀n"; return 0;}中：fish_length = fish_length/inches_per_foot； 用鱼的平均长度除以12是什么意思啊？是转换成什么呀？