loop question

[josh26757]

can someone explain why this loop calls the function in it?
when i called the function in the loop it called it twice.
i had the understanding that a loop laid out like != would just check a condition.
here is the code

do{menu();}
     while(selection(files) != true);

selection is declared bool.
tried to find a good explanation but couldn't.could someone go into detail about this?

[Zlatomir]

You need to debug the code and see what selection(files) returns.

And the difference between the do...while and while is in principle that do..while always executes the do code block at least once (even if the condition is false from the beginning)

So this code will print Foo once:

do {
std::cout << "Foo\n";
}
while(false);

And this code doesn't print Foo:

while(false) {
std::cout << "Foo\n";
}

[josh26757]

thank you
but i understand the dif. between do while and while
i think i understand what is going on.
if you call a function to check a condition it will actually call the entire function not just read the end result as i had assumed.
the entire function will run in order for the condition to be checked.
i thought it would check the last returned true or false and i was wrong.

[Lindley]

Yeah, if you stop to think about it for a moment, it will become clear why that would be much less intuitive from a programmer's perspective. Far simpler to just remember the rule----if you want to keep the last value returned by a function around somewhere, store it in a variable.