/*
 This is a program that tests the running time of binary search. It
 initializes an array of random numbers, and then calls binary search
 NB_TESTS times on it, each time with a randomly generated target.

 Laura Toma
 csci 101
*/


//to use random numbers
import java.util.Random;



public class BinSearchTest {
	
	public static void main (String args[]) {
		
		final int SIZE = 1000000; 
		final int NB_TESTS = 100000;

		// a random number generator
		Random rand = new Random();   
		
		//declare variable r that knows to read from user
		ReadStream r = new ReadStream(); 
		
		//declare and allocate array
		int[] a = new int [SIZE]; 

		//initialize array in increasing order
		int i=0; 
		while (i < SIZE) {
			a[i] =i;
			i++;
		}
		System.out.println("test array size: " + SIZE);

		int target, left, right, middle; 
		boolean found; 

		
		/* run NB_TESTS searches with a random target */

		// start for timing information
		long startTime = System.currentTimeMillis();
		i = 0;
		
		while (i< NB_TESTS) {
			
			//returns a random number in the range 0 to SIZE-1
			target = rand.nextInt(SIZE);
			//System.out.println("checking target = " + target);
			
			//binary search for target in a[]
			left = 0; right = SIZE-1;
			found = false; 
			while (right >= left && found == false) {
				middle = (left + right)/2;
				if (a[middle] == target) found = true; 
				if (a[middle] < target) left = middle +1; 
				if (a[middle] > target) right = middle -1; 
			}
			
			i++;
		}

		// end of timing
		long endTime = System.currentTimeMillis();
		
		// some timing statistics
		double totalTimeSeconds = (endTime - startTime)/1000.0;
		
		System.out.println(NB_TESTS + " binary searches done.");
		System.out.println("total time = " + totalTimeSeconds + " seconds");
		System.out.println("avg time per search = " + totalTimeSeconds/NB_TESTS + " seconds");
		
	} // end of main
	
} // end of class