i have been trying in vain to implement fibonacci in prolog, and so far i've done that in c++,javascript,python and java. but it just irritates me since i'm new to prolog and i just can't code much, because i haven't seen the prolog equivalents of c++'s for loops,if-else statements,basic variable usage etc.. but still i learnt whatever i could from 4-5 books i downloaded off the net, a few university lecture notes,etc.

here's my code to print N elements of the fibonacci series ( here N means excluding the first two basic elements of the series, 0,1.

```
start:-
write('Enter n '),nl,
read(N),
write('0 1'), %printing first two necessary numbers of the series
fib(N,0,1).
% so i'm reading N, the no of elements of the fibonacci series the user would like to %print,
fib(N,A,B):- % A and B are the n-2 and n-1 that add up to give n,
N>1,
C = A+B,
B = C,
A = B,
write(C),nl,
X is N-1,
fib(X,A,B). % i directly put N-1 as the first argument in previous versions..would that create problems?
```

also i tried to do it this way too:

```
fib(0, 0, A):-!.
fib(1, 1, A):-!.
fib(N, X, A):-
N1 is N-1,
N2 is N-2,
fib(N1, X1,1),
fib(N2, X2,0),
X is X1+X2.
display(X,A).
display(X,A):-
A==1,
write(X),nl.
```

the A argument in display is a flag. it means, whenever the brancing happens from N-1 side of the recursion, the sum will be printed then only.. otherwise it will print like this: 1 2 1 3 1 5 etc