How can I generate a random number between 1 and 3?
With this function I get sometimes 0(i only wanna have 1,2 or 3): 

```
ziehen=rand() % 3 + 1;

```

And why I have to add srand(0) in the main program?
I've added 

```
#include <stdlib.h>
#include <stdio.h>
#include <time.h>

```

to the Libaries. Is this enough or I need more?