Three Heads in a row Java Program?

Question

Write a program in JAVA that will simulate coin tosses and output the number of tosses required to get three “heads” in a row. This program will also output to the screen the “heads” and “tails” that it has simulated tossing. For example, your program may produce output as follows:

Example 1: HTHHH
5
Example 2: TTTHTHHTTTTHHH
14

Now when I run it, it continuous prints H and it runs infinite times. Its not flipping Tails either,only heads. So can someone help me fix my code Please.....Thank you.

My Code:

    import java.util.*;

public class threeHeads {

    public static void main(String[] args) {

        boolean first = false;
        boolean second = false;
        int count = 0;

        Random random = new Random();

          while(true){

                int n = random.nextInt(2) + 1; //1 is Heads, 2 is Tails 

                if (n == 1){
                    System.out.println("H");  
                    count++;

                if (first == false){
                    first = true;
                } else if (second == false){
                    second = true;
                } else if (second == true){
                    break;
                } 
                }
                else {
                    System.out.println("T");
                    first = false;
                    second = false;
                    count++;
                  } 

            }

          if (count == 3){
                System.out.println(count);
            }

    }
}

After the initial `int n = ...`, the whole rest of the while block is inside the `if (n == 1)` block until the very last two assignments (`first = false; second = false`). That means the loop will only do anything if `n == 1` -- otherwise it'll just go to the next iteration. (Things like this are one of the reasons proper formatting is very helpful!) — yshavit, Dec 08 '16 at 23:48
Also, you never need to check `someBoolean == true` or `someBoolean == false`. Just do `someBoolean` or `!someBoolean`. And if you have a check `if(!second)`, you don't need an `else if (second)` after it -- just `else` is sufficient, since if second isn't false, it must be true. And that leads us to the last bug, which is that your `System.out.println("T")` will only happen if `second != false` and `second != true` (otherwise the code will instead hit one of those two blocks), which of course is never the case. — yshavit, Dec 08 '16 at 23:51

score 1 · Accepted Answer · answered Dec 09 '16 at 00:24

give this code a try to see if it achieves what you want

public class flipper {
    public static void main(String[] args) {
        int heads = 0;
        int count = 0;
        while (heads < 3) {
            int flip = (int)(Math.random() * 2);  // range [0, 1]
            count++;
            if (flip == 0) {
                System.out.print("H");
                heads++;
            } else {
                System.out.print("T");
                heads = 0;
            }
        }
        System.out.println("\nIt took " + count + " flips to achieve three heads in a row");
    }
}

Three Heads in a row Java Program?

1 Answers1