In C++ I Cannot Grasp Pointers and Classes

By : timmyg
Source: Stackoverflow.com
Question!

I'm fresh out of college and have been working in C++ for some time now. I understand all the basics of C++ and use them, but I'm having a hard time grasping more advanced topics like pointers and classes. I've read some books and tutorials and I understand the examples in them, but then when I look at some advanced real life examples I cannot figure them out. This is killing me because I feel like its keeping me from bring my C++ programming to the next level. Did anybody else have this problem? If so, how did you break through it? Does anyone know of any books or tutorials that really describe pointers and class concepts well? or maybe some example code with good descriptive comments using advanced pointers and class techniques? any help would be greatly appreciated.

By : timmyg


Answers

Your problem seems to be the C core in C++, not C++ itself. Get yourself the Kernighan & Ritchie (The C Programming Language). Inhale it. It's very good stuff, one of the best programming language books ever written.



In a sense, you can consider "pointers" to be one of the two most fundamental types in software - the other being "values" (or "data") - that exist in a huge block of uniquely-addressable memory locations. Think about it. Objects and structs etc don't really exist in memory, only values and pointers do. In fact, a pointer is a value too....the value of a memory address, which in turn contains another value....and so on.

So, in C/C++, when you declare an "int" (intA), you are defining a 32bit chunk of memory that contains a value - a number. If you then declare an "int pointer" (intB), you are defining a 32bit chunk of memory that contains the address of an int. I can assign the latter to point to the former by stating "intB = &intA", and now the 32bits of memory defined as intB, contains an address corresponding to intA's location in memory.

When you "dereference" the intB pointer, you are looking at the address stored within intB's memory, finding that location, and then looking at the value stored there (a number).

Commonly, I have encountered confusion when people lose track of exactly what it is they're dealing with as they use the "&", "*" and "->" operators - is it an address, a value or what? You just need to keep focused on the fact that memory addresses are simply locations, and that values are the binary information stored there.

By : Dan


In the case of classes I had three techniques that really helped me make the jump into real object oriented programming.

The first was I worked on a game project that made heavy use of classes and objects, with heavy use of generalization (kind-of or is-a relationship, ex. student is a kind of person) and composition (has-a relationship, ex. student has a student loan). Breaking apart this code took a lot of work, but really brought things into perspective.

The second thing that helped was in my System Analysis class, where I had to make UML class diagrams. These I just really found helped me understand the structure of classes in a program.

Lastly, I help tutor students at my college in programming. All I can really say about this is you learn a lot by teaching and by seeing other people's approach to a problem. Many times a student will try things that I would never have thought of, but usually make a lot of sense and they just have problems implementing their idea.

My best word of advice is it takes a lot of practice, and the more you program the better you will understand it.



This video can help you solving your question :)
By: admin