(GATE CS 2004)GATE EXAM PREPARATION IN "C"

Consider the following program fragment for reversing the digits in a given integer to obtain a new integer. Let n = D1D2…Dm

int n, rev; rev = 0; while (n > 0) {    rev = rev*10 + n%10;    n = n/10; }

The loop invariant condition at the end of the ith iteration is:

a) n = D1D2….Dm-i and rev = DmDm-1…Dm-i+1
b) n = Dm-i+1…Dm-1Dm and rev = Dm-1….D2D1
c) n ≠ rev
d) n = D1D2….Dm and rev = DmDm-1…D2D1

Answer (a)