Why am i not getting the proper output? [duplicate]

Answer 1

Wow - aggressive downvoting! Give the new person a chance folks!

The answer is "scope". If you compile with gcc, you get a very obvious warning:

C:\tmp>gcc test.c
test.c: In function `func':
test.c:22: warning: function returns address of local variable

The local variable is lost when the function exits and its memory allocation cleaned up.

If you want to return an array from a function you have to malloc it to create a non-local memory allocation and then return the pointer.

Answer 2

You're returning a pointer to a local variable, which results in undefined behaviour.

The most common way to deal with functions that return arrays is to pass in the array from the caller, e.g. fixed version of your code:

void func(int arr[]);

int main()
{
    int arr[10];

    func(arr);

    for (int i = 0; i < 10; i++)
        printf("%d ", arr[i]);

    return 0;
}

void func(int arr[])
{
    for (int i = 0; i < 10; i++)
        arr[i] = i + 1;
}