I am trouble returning a pointer to an array back to main:
mainCode:int *funct(int argc, char *argv[]);
functionCode:int *a = funct (argc,argv); printf("%d\n ", a[1]);
Code:int *funct(int argc, char *argv[]) { //need argc, argv inside this function int arr[3] = {1,2,3}; return *arr; }
It makes no sense to return a pointer to data that no longer exists. Pass the array to a function.
7. It is easier to write an incorrect program than understand a correct one.
40. There are two ways to write error-free programs; only the third one works.*
When I do that I get the same error as before : "function returns address of local variable"
rhe error is caused by the return line
Last edited by Suchy; 03-02-2008 at 03:39 PM.
Of course because of the way local variables in functions are stored.
They live on the stack, and stacks are very temporary things, so you can not return the address of a variable that lies on the stack.
You will have to do something different.
The array must be either dynamically allocated and initialized in the function or statically allocated on the heap as a global variable, or a static function member.
Dynamic allocation is the best option, as you get a new copy with every call, but the caller must be then burdened with freeing the memory using a call to free.
A small but complete example.Code:int *getArray(); int main() { int *array; array = getArray(); array[1] = 4; free(array); return 0; } int *getArray() { int *a; a = malloc(3 * sizeof(*a)); return a; }
A typical example of ...cheap programming practices.Code:... goto johny_walker_red_label; johny_walker_blue_label: exit(-149$); johny_walker_red_label : exit( -22$);
Show the codeOriginally Posted by Suchy
Not it can be just function parameter - look at strcpy, it does nothing of the above and still fills the destination with some data and returns pointer to itThe array must be either dynamically allocated and initialized in the function or statically allocated on the heap as a global variable, or a static function member.
All problems in computer science can be solved by another level of indirection,
except for the problem of too many layers of indirection.
– David J. Wheeler
