Hi
I had the structure TIME:I initialized the variable timenow of type TIME as:Code:struct TIME {int h, m, float s;};
The instructor deducted the marks for this initialization with the reason that I should have declared it this way:Code:TIME timenow; timenow.h = 2; timenow.m = 5; timenow.s = 30;
But is my initialization incorrect? Does it initialize the variable? Please guide me. Thanks.Code:TIME timenow = { 2 , 5 , 30};
I'm an outright beginner. Using Win XP Pro and Code::Blocks. Be nice to me, please.
Both methods end up with the same result, but the corrected method is a literal initialization, where as yours is just setting the struct members on a non-initialized variable.
If you understand what you're doing, you're not learning anything.
On the strict definition of "initialization", no your code does not initialize. Your code runs the default initializer, and then later assigns (not initializes) the values to be 2, 5, 30. (EDIT: Also, you may or may not even have a default initializer available, if no constructor with () was defined.)
Last edited by tabstop; 05-18-2011 at 01:57 PM.
It might not be a good idea to use strictly uppercase for your structs. It's generally reserved for macros.
Originally Posted by Adak
Thank you, everyone.
tabstop: I'm sorry I couldn't understand the bold parts. Could you please explain them a bit? Thanks.
I'm an outright beginner. Using Win XP Pro and Code::Blocks. Be nice to me, please.
My EDIT should probably be ignored, as you have a POD struct with nothing fancy. But anyway: there's the idea of "default initializations", which is if you just type a variable declaration is what you get.
Since I didn't specify any initializers for these variables, they are all default-initialized. For basic types like char and int, default initialization is no initialization at all -- whatever value that chunk of memory had beforehand is still there. For a class like std::string, there's a constructor that takes no arguments that is run when you do default initialization. When you declare a struct with no initializers like you did, each of the members is default-initialized (in your case, to random numbers).Code:int main() { char a; int b; std::string c; }
I realize in C++ structs are just like classes, and I just got done reading about this last night. Pretty much you rely on the default constructor when assigning vars inside the object, but when you create a constructor the compiler says "get lost" and takes away the default constructor you had been relying upon.
Last edited by xentaka; 05-20-2011 at 06:39 PM.
