Honestly stuck

Question

The exercise is to create the ever annoying "knock knock who's there banana banana who?" joke, the problem is that I don't quite get the do-while and if concepts, can someone help explain them to me?

KnockKnock.java

/*  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?
    ...as long as Person A has answered Banana the above repeats endlessly
    ...assuming the person answers Orange we'd see
    Person B:  Orange who?
    ...and then the punchline.
    Person A:  Orange you glad I didn't say Banana again?
    (It's a really bad joke that makes it sound like "Aren't you glad I didn't say Banana again?")

    Let's just assume the only two words passed in from the console from Person B are either banana or orange.
*/

// ====BEGIN PROMPTING CODE====

// Person A asks:
console.printf("Knock Knock.\n");

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

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

// ==== END PROMPTING CODE ====

Answer 1 · 2015-04-15T00:06:29Z

April 15, 2015 12:06am

Hey there Pedram,

You first want to wrap the code in a do while loop, which has the syntax

do { //code to run while (condition to be met that breaks loop)

So this would look like.

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?  ");

// Person B responds:
console.printf("%s who?\n", who);
} while(who.equalsIgnoreCase("banana"));
console.printf("%s you glad I didn't say Banana?", who);

Remember to declare who outside of the loop so that it can be used by console.printf statement after the loop, because without it the scope would only make the variable accessible to the loop.

Thanks, let me know if you are still left with questions, and I'll help further.

Answer 2 · 2015-04-15T00:33:10Z

April 15, 2015 12:33am

An easy way I learned do-while loops is to understand the difference between them and a regular while loop.

while loop: is considered a pre-check. This means it will check if the conditions are true (which are in the parenthesis "( conditions placed here )" after the word "while") and then proceed to do the code placed after the curly braces "{code here}", and WHILE the condition is true it will continue to repeat the code in the curly braces until the condition reaches false.

Example format

while ( condition placed here){

       code you want the loop to perform placed here;

"}"

do-while: Instead of a pre-check it is the opposite. It is a post check, meaning it will run code after the "do" and curly braces ONCE without having to be checked in the WHILE condition, and then check the conditions afterwards in the parenthesis after the word WHILE. If the condition in the while section is true it will repeat the code after the "do" over and over again until the conditions in the while section is FALSE.

Example format

do{

       place your code here that you want to be done;

" ^remember that code above will be done once without having to check the WHILE CONDITION, but only once. Every time after the do it needs to check with the WHILE CONDITION."

} while ( set condition here )```

Hopefully you were able to get a better understanding of how those loops work. If you still have trouble don't be hesitant to ask.

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Pedram Namiranian

Pedram Namiranian

Honestly stuck

2 Answers

Rob Bridges

Rob Bridges

Alexander Bueno

Alexander Bueno