BinarySearch.java

class BinarySearch {
    int doSearch(int arr[], int targetValue)
        {
            int min = 0;
            int max = arr.length - 1;
            int guess;
            
            while (min <= max)
            {
                // split the array in half
                guess = min + (max - min) / 2;
                
                // if the target value is found, return the index
                // of the array
                if(arr[guess] == targetValue)
                {
                    return guess;
                }
                // if the value is less than the target, raise
                // the minimum value by one
                else if(arr[guess] < targetValue)
                {
                    min = guess + 1;
                }
                // if the value is greater than the target, lower
                // the maximum value by one
                else 
                {
                    max = guess - 1;
                }
            }
            // if the value is not present, return -1
            return -1;
        }
    public static void main(String[] args)
    {
        BinarySearch bs = new BinarySearch();
        int primes[] = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 
		41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97};
		
		int targetValue = 97;
        
        int result = bs.doSearch(primes, targetValue);
        
        if (result == -1)
			System.out.println("Number not present");
		else
			System.out.println("Number found at index "
							+ result);
    }
}