C / C++ / MFC

Eranga Thennakoon wrote:

Ok, thanks a lot pal. Now I got the point. At the same time. One of friend says that, as a good practice in programming, as much as possible it is better to avoid global variables and used member variables. Is that true?

Eranga Thennakoon wrote:

Why I'm asking is, one is that I'm really new for C++, two is I most familiar with Java and there is no such a way, so that those tips can be really helpful to me

CPallini wrote:

Well if you're familiar with Java then you should be familiar with OOP principles too, such encapsulation and information hiding that both go against global variables usage.

I appreciate your help all the time...
Eranga

class A
{
public:
  A() {
    cout << "A(), and going to throw! \n";
    throw 3;
  }
};

A obj; // Global. Will throw when initialization!
void main()
try {
}
catch(...) { // catch all, but it just can not catch what being thrown in A::A()
}

using namespace std;

class Foo{

public:

	Foo ();
};

Foo::Foo()
try{
	cout << "constructing" << endl;

	throw(0);

} catch (...)
{
	cout << "catch exception in constructor" << endl;
}


Foo foo;

int main()
{
	int i = 0;

	cout << i;

	return 0;
}

try { // <---  Compile-error at this line.
  A obj; // To throw something.
}
catch(...) {
}
void main()
{
}

George_George wrote:

No words like local or global catch.

George_George wrote:

"there is no way to catch exceptions from the initialization of global variables (section 14.7)"

George_George wrote:

This will catch every exception, except those thrown by construction and destruction of global variables. There is no way of catching exceptions thrown during initialization of global variables. The only way of gaining control in case of throw from an initializer of a nonlocal static object is set_unexpected ($14.6.2). This is another reason to avoid global variable whenever possible.

int main()
try {
}
catch(std::range_error) {
}
catch(std::bad_alloc) {
}
catch(...) {
}