binary search on character array in java

I want to know how to do binary search on character array in java

There is a in-build function in java , but i don't want to use that , any help or pointers will be really appreciated.

I just started with below as i know binary search needs the array to be sorted

char[] whitelist = {'f','e','d','c','b','a'};

                Arrays.sort(whitelist);

                for (char ch : whitelist) {  
       开发者_运维知识库             System.out.println("The values after sorting\n"+ch);
                }

---

As simple as Java does:

int binarySearch(char[] a, char key) {
    int low = 0;
    int high = a.length - 1;

    while (low <= high) {
        int mid = (low + high) >>> 1;
        char midVal = a[mid];

        if (midVal < key)
            low = mid + 1;
        else if (midVal > key)
            high = mid - 1;
        else
            return mid; // key found
    }
    return -(low + 1);  // key not found.
}

Of course, replace the array a with your array, i.e. whitelist.

Basically, look out for this - http://en.wikipedia.org/wiki/Binary_search_algorithm#Iterative