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Java Java Basics Perfecting the Prototype Looping until the value passes

Chigozie Ofodike
Chigozie Ofodike
11,197 Points
Posted by Chigozie Ofodike
Chigozie Ofodike
11,197 Points

How do I stop this infinite loop?

I think my program is running infinitely, is it? If so why is it? And how i stop it?

Example.java 
// I have initialized a java.io.Console for you. It is in a variable named console.
String response;
boolean answerYes;
do{
  response = console.readLine("Do you understand do while loops?  \n");
  answerYes = (response.equalsIgnoreCase("no"));
}while(response.equals(answerYes));

1 Answer

David Garner
David Garner
4,181 Points
David Garner
David Garner
4,181 Points

Yes, your code runs in a infinite loop. This is because you are comparing a String response with a boolean answerYes.

The equalsIgnoreCase() returns type boolean. You used this correctly when assigning the value to answerYes here:

answerYes = (response.equalsIgnoreCase("no"));

However here:

while(response.equals(answerYes));

is where you compare the string response with answerYes.

Because answerYes is a boolean you can use it as the condition for the do-while loop like this:

String response;
boolean answerNo; //change to answerNo for better readability of code
do{
  response = console.readLine("Do you understand do while loops?  \n");
  //answerNo equals true if the response equals "no", it equals false other wise  
  answerNo = (response.equalsIgnoreCase("no")); 
}while(answerNo); // while answer is true keep running the code