please help me ! how to do this

Create an array (say int a[]) mapping input (the index of the array item) to the output (the value of the array item).
Then, for each input i you produce the output a[i].


[update]
It is really simple (bound checking left to the reader).

int output(int input)
{
  static int a[] = {1,2,3,4,5,6,7,8,9,1,0,1,1,1,2,1,3,1,4};
  return a[input];
} 

[/update]