/*
 * A few places where "const" is commonly seen
 */
#include<iostream>
using namespace std;

const double PI = 3.141592653;
#define PIC 3.141592653

void square(int &x){
	x *= x;
}

void pointer_square(int *x){
	*x *= *x;
}

void print(const int &x){ // If you take 
	cout << "The parameter was:  " << x << endl;
}

int find_half(const int &x){
	return x/2;
}

class fox {
public:
	int length;
	string name;
	fox(int l, string n) : length(l), name(n) {}
	// void enlongate(fox *this){
	void enlongate(){
		this->length++;
	}
	// int getLength()(const fox *this){
	int getLength() const {
		return this->length;
	}
	~fox(){
		cout << this->name << " has been discarded with length " << this->length << " and address " << this << endl;
	}	

};

void enlongate_anyway(const fox& tostretch){
	void* e = (void*)&tostretch;
	((fox*)e)->enlongate();
	((fox*)((void*)&tostretch))->enlongate();
}

// Copying classes, references in C++, const reference, etc.
void stretch(fox tostretch){
	cout << "Lengthening " << tostretch.name << endl;
	tostretch.enlongate();
	tostretch.enlongate();
	cout << "After Lengthening, final length is " << tostretch.length << endl;
}

int main(){
	const int unchangeable = 10;
//	square(unchangeable); // Can't do this, because it would change x!
	int z = 20;
	square(z);
	pointer_square(&z);
	cout << "z = " << z << endl;
	print(unchangeable);
	cout << "Half of unchangeable = " << find_half(unchangeable) << endl;
	fox snake(30, "Snake");
	const fox clearwater(32, "Clearwater");
	snake.enlongate();
//	clearwater.enlongate(); // Can't do that!  clearwater is a "const fox"
	clearwater.getLength(); // This is ok, because getLength is a const method
	fox extra = clearwater;
	stretch(extra);

	size_t Arr[] = {2, 3, 4, 7, 8, 9};
	auto x = Arr[3];
	cout << sizeof(x) << endl;
	for(auto &i : Arr)
		i *= 400;

	for(const auto &i : Arr)
		cout << "i = " << i << endl;

	enlongate_anyway(extra);
	cout << "After enlongate_anyway, extra has a length of " << extra.length << endl;

	return 0;
}