import java.util.Random;

/**
 * An example of using a hashtable to check that a random string generator 
 * actually is generating random strings
 * 
 * @author gtowell
 * created: Sep 28, 2022 gtowell 
 */
public class UseHT {
    // the hash table to hold random strings
    // I do not actually care about the value.
    private SepChainHT<String, Integer> hashT;
    // an instance of the Java random number generator
    private Random rand; 

    /**
     * Initialize the instance
     */
    public UseHT() {
        hashT = new SepChainHT<>(10001);
        rand = new Random();
    }

    /**
     * Generate a random string of the given length.
     * This uses only lower case letters.
     * @param len the length of the random string
     * @return the random string
     */
    private String randomString(int len) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < len; i++) {
            sb.append('a' + rand.nextInt(26));
        }
        return sb.toString();
    }

    /**
     * Do the testing of the random string generator. It will test 
     * random strings of length 2 .. 4 and for each length will generate
     * between 10 and 100000 strings.   The idea is to see how many unique strings
     * I get.   If too few, then something is probably wrong with the generator
     */
    public void querrier() {
        for (int i = 2; i < 5; i++) { // the length of the random string to make
            for (int j = 10; j < 100001; j = j * 10) { // the number of random strings to make
                hashT = new SepChainHT<>(j*2); // clear the hashtable and init with lots of room.
                for (int k = 0; k < j; k++) {  // actually do the work of making the strings and putting them into the hashtable.
                    String s = randomString(i);
                    hashT.put(s, 1);
                }
                System.out.println(
                        "Random String length: " + i + " number generated " + j + " number unique " + hashT.size());
            }
        }
    }
    public static void main(String[] args) {
        (new UseHT()).querrier();
    }
}