Question

Disclosure: This is university work. I am not expecting code to accomplish my task rather I want to understand how best to manipulate strings in C.

I need to write a function to manipulate a string in a certain way (I’m not saying what so as to ensure that no-one provides exact code).

In python I’d just do the following

def foo(str):
  return str

Clearly things aren’t as easy as that in C.

Can anyone tell me how best to achieve this. Should I use pointers to simulate passing by reference and just manipulate the original string? Any help / resources would be greatly appreciated.

Update: I do want to preform an operation on the string and return the result of that operation (also a string). I am happy to manipulate the original string or return it. Which ever would be considered best practice.

The task I’ve been set is based on how to do that operation so I didn’t want to make that explicit.

So the Python would be:

def foo(str):
  #do something to str (which doesn't change it's length)
  return str

Answer 1

There are two ways:

1. If you manipulate the original string you don’t need to return anything
2. If you don’t want to change the original string you should copy it with strdup or malloc + strcpy and return a pointer (char *) to it. The caller of course must free it when done.

It all rests on the question: will the caller need the original string ?