Algorithm to find duplicate in an array -

i have assignment create algorithm find duplicates in array includes number values. has not said kind of numbers, integers or floats. have written following pseudocode:

 findingduplicatealgorithm(a) // array       mergesort(a);        int <- 0 i<a.length            if a[i] == a[i+1]                  i++                return  a[i]            else                  i++ 

have created efficient algorithm? think there problem in algorithm, returns duplicate numbers several time. example if array include 2 in 2 two indexes have ...2, 2,... in output. how can change return each duplicat 1 time? think algorithm integers, work float numbers too?

to handle duplicates, can following:

if a[i] == a[i+1]:     result.append(a[i]) # collect found duplicates in list     while a[i] == a[i+1]: # skip entire range of duplicates          i++               # until new value found