Passing string to a function in C - with or without pointers

Question

When I m passing a string to the function sometimes I use  char  functionname char  string name 256     and sometimes I use it without pointers  for example   char functionname char string 256     My question is when do I need to use pointers   Often I write programs without pointers and it works but sometimes it doesn t

User · Accepted Answer

The accepted convention of passing C-strings to functions is to use a pointer:

void function(char* name)

When the function modifies the string you should also pass in the length:

void function(char* name, size_t name_length)

Your first example:

char *functionname(char *string name[256])

passes an array of pointers to strings which is not what you need at all.

Your second example:

char functionname(char string[256])

passes an array of chars. The size of the array here doesn't matter and the parameter will decay to a pointer anyway, so this is equivalent to:

char functionname(char *string)

See also this question for more details on array arguments in C.

User · Answer

Assuming that you meant to write  char  functionname char  string 256     Here you are declaring a function that takes an array of 256 pointers to char as argument and returns a pointer to char  Here  on the other hand   char functionname char string 256     You are declaring a function that takes an array of 256 chars as argument and returns a char   In other words the first function takes an array of strings and returns a string  while the second takes a string and returns a character

User · Answer

An array is a pointer  It points to the start of a sequence of  objects    If we do this    nt arr 10    then arr is a pointer to a memory location  from which ten integers follow  They are uninitialised  but the memory is allocated  It is exactly the same as doing int  arr   new int 10

[c] Passing string to a function in C - with or without pointers?

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