Using a for loop:
int firstBig(int i) { for(int k = i; k != 0; k = next(k)) { if(k > 100) return k; } return 0; }
Using a while loop:
int firstBig(int i) { int k = i; while(k != 0) { if(k > 100) return k; k = next(k); } return 0; }