[Dev-C++] C++ pointers

[Green, A. <JA...@GA...>]

This may be OT, but I know I've seen programming questions here before, so I'll give it a try.

I wrote up a small program that tries to explain how pointers work to me.

#include <iostream>

double* f(double *pD2)
{
	*pD2 = 15;
	return pD2;
}

int main()
{
	double d;
	double *pD = &d;
	d = 20;
	*pD = 10;
	std::cout << *pD << '\n';
	std::cout << d << '\n';
	double *pD3 = f(&d);
	std::cout << d << '\n';
	std::cout << *pD3 << '\n';
	d = 100;
	std::cout << d << '\n';
	std::cout << *pD3 << '\n';
	std::cout << *pD << '\n';


	return 0;
}


The last parts of the output are 100   100   100.  My question is:  Why does *pD3 change when it points to a function that changes whatever is at &d ?  I thought calling cout would run that function again, or at least give me the same value as before.