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Java Java Basics Perfecting the Prototype Looping until the value passes

Kyla Thompson
Kyla Thompson
3,831 Points
Posted by Kyla Thompson
Kyla Thompson
3,831 Points

Java Basics: Knock Knock Joke help

Need help getting pass this exercise. Not sure what I need to do to fix my code: 

console.printf("Knock Knock.\n"); 
String who = console.readLine("Who's there?  "); 
boolean banana;
do {
    console.printf("%s who?\n", who);
    banana = (who.equalsIgnoreCase("banana"));
  if (banana) {
    console.printf("%s who?\n", who);
  }
}while (banana);
Ken Alger
Ken Alger
Treehouse Teacher
Ken Alger
Ken Alger
Treehouse Teacher

Edited for markup.

Ken

9 Answers

Gunjeet Hattar
Gunjeet Hattar
14,483 Points

Read the comments and code below. We want to move that prompting code into a do while loop. Wrap the code into a do while and check in the condition to see if who equals "banana" so the loop continues. Remember to move your who declaration outside the do block.

Now if I break down the question

1) First the question asks you to move the promoting code inside a do while loop & your who declaration outside the do block. 

String who; // declare who  string variable outside who block
do 
{
// put promoting code inside do while block
console.printf("Knock Knock.\n");
who = console.readLine("Who's there?  ");
console.printf("%s who?\n", who);
}

2) Check in the condition to see if who equals "banana" so the loop continues

String who;
do 
{
console.printf("Knock Knock.\n");
who = console.readLine("Who's there?  ");
console.printf("%s who?\n", who);
}
while(who.equals("banana")); // check the condition using Java's equal() method

Try breaking down the question, it helps. And any special reason why you used a boolean variable. It's fine in its way, but you did not initialise the banana boolean in the first place.

I don't like giving away codes, but i just wanted you to get a clear understanding

Hope this helps

Ken Alger
STAFF
Ken Alger
Treehouse Teacher
Ken Alger
Ken Alger
Treehouse Teacher

Kyla;

Let's walk through this challenge together.

Task 1

Read the comments and code below. We want to move that prompting code into a do while loop. Wrap the code into a do while and check in the condition to see if who equals "banana" so the loop continues. Remember to move your who declaration outside the do block.

Here is the code and comments we are given:

/*  So the age old knock knock joke goes like this:
        Person A:  Knock Knock.
        Person B:  Who's there?
        Person A:  Banana
        Person B:  Banana who?
        ...This repeats until Person A answers Orange
        Person A:  Orange
        Person B:  Orange who?
        Person A:  Orange you glad I didn't say Banana again?
*/

//Here is the prompting code
console.printf("Knock Knock.\n");
String who = console.readLine("Who's there?  ");
console.printf("%s who?\n", who);

For task 1 we need to create the do...while loop and meet the task requirements. Let's look at this with some basic problem solving methods (Prepare, Plan, Perform, and Perfect). We'll likely leave the Perfect stage until later.

Prepare

We have watched the video lessons, and have the tools we need, we have the same output for which we are aiming in the code comments.

Plan

Here is what we are asked to do broken down into steps...

  1. Move the prompting code into a do...while loop.
  2. Check to see if the variable who is equal to banana.
  3. They gave us a hint/tip of moving the who declaration outside the do block.

Perform

Our code would then need to look something like:

String who;
do {
console.printf("Knock Knock.\n");
who = console.readLine("Who's there?  ");
console.printf("%s who?\n", who);
} while(who.equalsIgnoreCase("banana"));

Does that make any sense?

Ken

HONG ZUO GAN
HONG ZUO GAN
12,805 Points

Thanks =)

Adam Tatusko
Adam Tatusko
16,589 Points
Adam Tatusko
Adam Tatusko
16,589 Points

Those were epic answers to the Code Challenge. :-)

Adam Tatusko
Adam Tatusko
16,589 Points
Adam Tatusko
Adam Tatusko
16,589 Points

Luis,

You are declaring the String variable who twice in your code. You can't do that. After you write

String who;

you then only refer to the variable by its name to utilize it or set it equal to a string, e.g.,

who = "Banana";
Kyla Thompson
Kyla Thompson
3,831 Points
Kyla Thompson
Kyla Thompson
3,831 Points

Thanks Gunjeet! This is extremely helpful!

Enrique Bernal
Enrique Bernal
3,584 Points
Enrique Bernal
Enrique Bernal
3,584 Points

Bummer for me:

JavaTester.java:101: error: variable who is already defined in method run() String who; ^ 1 error

/* So the age old knock knock joke goes like this: Person A: Knock Knock. Person B: Who's there? Person A: Banana Person B: Banana who? ...This repeats until Person A answers Orange Person A: Orange Person B: Orange who? Person A: Orange you glad I didn't say Banana again? */

//Here is the prompting code console.printf("Knock Knock.\n"); String who = console.readLine("Who's there? "); console.printf("%s who?\n", who); String who; do { console.printf("Knock Knock.\n"); who = console.readLine("Who's there? "); console.printf("%s who?\n", who); } while(who.equalsIgnoreCase("banana"));

Gunjeet Hattar
Gunjeet Hattar
14,483 Points

String who = console.readLine("Who's there? "); String who;

You have two instances of the same variable called who. Not possible in Java. You change one to Who or WHO but cannot be the same.

Jim Lamkin
Jim Lamkin
481 Points
Jim Lamkin
Jim Lamkin
481 Points

Thanks Ken!!

bienvenue byishimo
bienvenue byishimo
1,153 Points
bienvenue byishimo
bienvenue byishimo
1,153 Points

String who; do { console.printf("Knock Knock.\n");

// Person B asks and Person A's response is stored in the String who: who = console.readLine("Who's there? "); String WHO;

// Person B responds: console.printf("%s who?\n", who); } while (who.equalsIgnoreCase ("banana"));

MUZ140265 Blessing Kabasa
MUZ140265 Blessing Kabasa
4,996 Points
MUZ140265 Blessing Kabasa
MUZ140265 Blessing Kabasa
4,996 Points

for the first one you can do as follows. String who;

do {
    console.printf("Knock Knock.\n");
    who = console.readLine("Who's there?  ");
    console.printf("%s who?\n", who);
} while (who.equalsIgnoreCase("banana"));

but for the second task you can use the if statement as follows

if (who.equalsIgnoreCase("orange")){
console.printf("%s i am glad you are not another Banana", who);
}