Question

I have just begun using C everyday and was wondering, besides data structures (eg, link list, binary tree etc) are there any other use for pointers? Note: Edited

Answer 1

C has no built-in method of passing by reference. Pointers are a good way to implement that.

You need passing by reference if you want to:

• modify the arguments that you were given, for instance if your function has more than one return value.
• pass a large structure to a function without copying it entirely, which could be very wasteful in time and memory.

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C also has no built-in variable-size data structures. If you need an array whose size is only known at runtime, the only two ways of getting it are:

1. estimate the maximum size and always allocate it.
2. malloc it, which will give you a pointer to work with.

Obviously, option 1 is bad because:

1. it’s wasteful, if you rarely need the maximum size.
2. if the maximum needs to change, you have to recompile.

This leaves you with option 2, which requires pointers. This would not necessarily be true if C had references, but as I said before, it doesn’t.

I could probably think of many other uses if I gave it more time.

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You can use function pointers to wrap a common functionality around various functions.