A Crash Course in C

Arrays as function arguments

A function may not return an array.
Passing arrays does not make a copy of the array.
Arrays in the arguments of functions are really pointers.

The following functions are all the same:

void func(long array[5]);
void func(long array[]);
void func(long array[17]);
void func(long *array);

Here's an example:

long n[5];

void func(long array[5])
{
    int i;
    for (i = 0; i < 5; i++) {
        array[i] = i;
    }
}

int main()
{
    int i;
    printf("Array values are %d %d %d %d %d\n", n[0], n[1], n[2], n[3], n[4]);
    func(n);
    printf("Array values are %d %d %d %d %d\n", n[0], n[1], n[2], n[3], n[4]);
    return(0);
}

Output

Array values are 0 0 0 0 0
Array values are 0 1 2 3 4

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