// This program contains several small examples discussed in the CSE143X
// lecture that are relevant to the Bagels program.  Each small example has
// been turned into its own method.

import java.util.*;

public class Examples {
    public static void main(String[] args) {
        Scanner console = new Scanner(System.in);
        guessingGame(console);
        sayCheese(console);

        // make a string with 10 occurrences of "hello"
        String s = repeat("hello", 10);
        System.out.println("s = " + s);
                
        // sample call to replace the 'e' at index 1 with an asterisk
        s = replace(s, 1, '*');
        System.out.println("s = " + s);
    }
        
    // This short example allows a user to guess a number between 1 and 5.  The
    // user is asked to enter 0 to stop the game.  The method reports the
    // percent correct rounded to one digit after the decimal.
    public static void guessingGame(Scanner console) {
        Random r = new Random();
        int count = 0;
        int correct = 0;
        System.out.print("guess (0 to quit)? ");
        int guess = console.nextInt();
        while (guess != 0) {
            int answer = r.nextInt(5) + 1;
            count++;
            if (guess == answer) {
                System.out.println("correct");
                correct++;
            } else {
                System.out.println("no, it was " + answer);
            }
            System.out.print("guess (0 to quit)? ");
            guess = console.nextInt();
        }
        double percent = 100.0 * correct / count;
        System.out.println("percent = " + round1(percent));
    }

    // This method demonstrates the need to use the equals method when
    // comparing strings.  It produced the wrong results with the test
    // (cheese == "cheese")
    public static void sayCheese(Scanner console) {
        System.out.print("say cheese: ");
        String cheese = console.next();
        if (cheese.equals("cheese")) {
            System.out.println("you said cheese");
        } else {
            System.out.println("you're an idiot");
        }
    }

    // returns a string composed of times occurrences of text
    public static String repeat(String text, int times) {
        String result = "";
        for (int i = 0; i < 10; i++) {
            result = result + "hello";
        }
        return result;
    }

    // pre : 0 <= index < s.length()
    // post: returns the string obtained by replacing the character at the
    //       given index with ch
    public static String replace(String s, int index, char ch) {
        return s.substring(0, index) + ch + s.substring(index + 1);
    }
        
    /*
    // variation of replace that throws an exception if the precondition is
    // violated
    public static String replace(String s, int index, char ch) {
        if (index < 0 || index >= s.length()) {
            throw new IndexOutOfBoundsException();
        }
        return s.substring(0, index) + ch + s.substring(index + 1);
    }
    */

    // returns the result of rounding n to 1 digit after the decimal point
    public static double round1(double value) {
        return (int) (10 * value + 0.5) / 10.0;
    }
}