Thread: Find an unique number in an array

You have integer array of 2n+1 elements, in which n numbers are having its 2 entries.
You have to find the 1 number which is unique in the the array.

e.g:
{1,9,8,6,7,5,3,4,2,2,9,8,7,6,4,3,1}

you program should give 5

do xor of all element of array..