Question

C++ question: Just learning the language coming from Python... I'm trying to implement a Grid class but am a little unsure how to do it (still learning syntax...) How do I initiate it?
Grid gridGenerator(10, 10) ? int gridGenerator = Grid(10,10)? I see the notation Grid name(someNum, someNum) and the 'Grid' part confuses me. Also, do I always need to initiate variables like this: int x; x = 5 or can I do: int x = 5 ? Thanks!

Answer 1

sorry about the crappy punctuation... I lost some 'returns'.

Answer 2

about the second part (declaring and defining variables):

in C++ (and maybe in C), yes it is possible to declare variables and assign a value to them in the same line. So int x = 5; is legal :-D

Answer 3

Yes, it is legal in C. Not only that, but Valgrind shows uninitialized variables as errors, and you can set up flags for gcc to do the same, I believe. At least, you can set it to raise warnings.

Answer 4

Thanks for that. What is Valgrind? Compiler? I'm using Visual Studio... Anyone familiar with setting up/initiating Grids?

Answer 5

My answer was more for agdgdgdgwngo. valgrind is a tool to check for memory leaks, heap usage, and some other stuff in C programs. I don't think you can use with sepples, but I never tried.

Answer 6

The <int> part is what is called a template. They're a pretty complex beast, but in this case they're basically being used to say “I want a grid of ints”; this as opposed to a grid of, say, floats (which can store decimal numbers), or a grid of UI elements, etc.

Because of the way C++ works, this:

Grid<int> gridGenerator(10, 10);

Is actually equivalent to saying:

Grid<int> gridGenerator = Grid<int>(10,10);

In fact, it may be the only way to say the above. So it's the equivalent of saying int x = 5.

Answer 7

shadowfiend, thanks. That's exacly what I was after and it turns out the reason I had some trouble is due to not importing the library I needed. Thought the assignment files took care of it but they did not. I'm beginning to find that C++ is a much trickier beast than Python. Is a good technique to build a little at a time and test with compiling? It's a lot harder to debug without the translator as in Python, no? Any tricks? Thanks again.

Answer 8

You're right; one reason Python was so much easier to learn/understand was because of the REPL/interpreter thing that came with it.

If you want to debug your C++ programs, you should learn to use a debugger like gdb.

Also, you can use the assert() macro from #include <cassert> or #include <assert.h>, which works similar to in Python
http://www.cplusplus.com/reference/clibrary/cassert/assert/

Answer 9

Absolutely would go for incremental work + compilation. In a perfect world, your IDE (Visual Studio) warns you of issues beforehand, but sometimes the world isn't perfect :)

The upside of a compiler is that you get rid of certain types of errors before you run your program. The downside is it's a different workflow from just having an interpreter and REPL.

Answer 10

I agree. Thus far I've found the compiler errors and incremental work are solving most of my problems. The hardest part is tracking down exactly what the compiler errors mean...