syntax is of objective c is
returnObj = [object functionName: parameters];
Where object is the object which has the method you're calling. If you're calling it from the same object, you'll use 'self'. This tutorial might help you out in learning Obj-C.
In your case it is simply
[self score];
If you want to pass a parameter then it is like that
- (void)score(int x) {
// some code
}
and I have tried to call it in an other method like this:
- (void)score2 {
[self score:x];
}