// Chapter 17, exercise 01: output format of pointer value

// Exercise 02: how many bytes in an int, double, bool? Don't use sizeof()

#include <sstream>
#include <iostream>
#include <vector>
using namespace std;

// take a pointer and return its address as an int
int ptr_to_int(void* ptr) {
	ostringstream oss;
	oss << ptr;
	istringstream iss(oss.str());
	int adr_int;
	iss >> hex >> adr_int;
	if (!iss) cerr << "problem reading address\n";
	return adr_int;
}

struct X { int a, b, c; };

struct V {
	int a, b, c;
	virtual void f() { }
};

int main() {
	// 1
	cout << "Output format of a pointer:\n";
	int* pi = new int(0);
	cout << "int* pi is " << pi << "\n";
	cout << "&*pi is " << &*pi << "\n";
	cout << "&pi[1] is " << &pi[1] << "\n";
	delete pi;

	// 2
	cout << "\nNumber of bytes of different types:\n";
	pi = new int[2];
	pi[0] = 0;
	pi[1] = 0;
	// subtract pointers from each other to get size
	int var_size = ptr_to_int(&pi[1]) - ptr_to_int(pi);
	cout << "int: " << &pi[1] << " - " << pi << " = " << var_size << " bytes.\n";
	cout << "sizeof(int): " << sizeof(int) << "\n";
	delete[] pi;

	char* pc = new char[2];
	pc[0] = 0;
	pc[1] = 0;
	var_size = ptr_to_int(&pc[1]) - ptr_to_int(pc);
	cout << "char: " << (void*)&pc[1] << " - " << (void*)pc << " = " << var_size << " bytes.\n";
	cout << "sizeof(char): " << sizeof(char) << "\n";
	delete[] pc;

	double* pd = new double[2];
	pd[0] = 0;
	pd[1] = 0;
	var_size = ptr_to_int(&pd[1]) - ptr_to_int(pd);
	cout << "double: " << &pd[1] << " - " << pd << " = " << var_size << " bytes.\n";
	cout << "sizeof(double): " << sizeof(double) << "\n";
	delete[] pd;

	bool* pb = new bool[2];
	pb[0] = 0;
	pb[1] = 0;
	var_size = ptr_to_int(&pb[1]) - ptr_to_int(pb);
	cout << "bool: " << &pb[1] << " - " << pb << " = " << var_size << " bytes.\n";
	cout << "sizeof(bool): " << sizeof(bool) << "\n";
	delete[] pb;

	X* pX = new X[2];
	var_size = ptr_to_int(&pX[1]) - ptr_to_int(pX);
	cout << "struct X: " << &pX[1] << " - " << pX << " = " << var_size << " bytes.\n";
	cout << "sizeof(X): " << sizeof(X) << "\n";

	V* pV = new V[2];
	var_size = ptr_to_int(&pV[1]) - ptr_to_int(pV);
	cout << "struct V: " << &pV[1] << " - " << pV << " = " << var_size << " bytes.\n";
	cout << "sizeof(V): " << sizeof(V) << "\n";
}
/*
sizeof(int): 4
problem reading address
problem reading address
char: 0000019B515B5E11 - 0000019B515B5E10 = 0 bytes.
sizeof(char): 1
problem reading address
problem reading address
double: 0000019B515BF538 - 0000019B515BF530 = 0 bytes.
sizeof(double): 8
problem reading address
problem reading address
bool: 0000019B515B5E11 - 0000019B515B5E10 = 0 bytes.
sizeof(bool): 1
problem reading address
problem reading address
struct X: 0000019B515BCDFC - 0000019B515BCDF0 = 0 bytes.
sizeof(X): 12
problem reading address
problem reading address
struct V: 0000019B515C1E68 - 0000019B515C1E50 = 0 bytes.
sizeof(V): 24
*/