HDU 2095 Find your Present (XOR)

Test instructions The number of only odd numbers in a set of numbers to ensure that only one number satisfies

Knowing a number with your own XOR equals 0 vs. 0 or equals yourself on the line

#include <cstdio>using namespace Std;int main () {    int n, t, ans;    while (scanf ("%d", &n), N)    {        ans = 0;        for (int i = 1; I <= n; ++i)        {            scanf ("%d", &t);            Ans = ans ^ t;        }        printf ("%d\n", ans);    }    return 0;}

Find your present (2)
problem Descriptionin the New Year party, everybody'll get a "special present". Now it's your turn to get your special present, a lot of presents now putting on the desk, and only one of the them would be yo Urs. Each present have a card number on it, and your present ' s card number would be the one that different from all the others, a nd you can assume this only one number appear odd times. For example, there is 5 present, and their card numbers are 1, 2, 3, 2, 1.so your present would be is the one with the card n Umber of 3, because 3 is the number, which different from all the others. 
InputThe input file is consist of several cases.
Each case would be presented by an integer n (1<=n<1000000, and n are odd) at first. Following that, n positive integers would be given in a line, all integers would smaller than 2^31. These numbers indicate the card numbers of the PRESENTS.N = 0 ends the input. 
Outputfor each case, output an integer in a line, which is the card number of your present. 
Sample Input

51 1 3 2 231 2 10

 
Sample Output

32

HDU 2095 Find your Present (XOR)