Java

do-while loop & other stuff

Please support our Java advertiser: Programming Forums - DaniWeb Sister Site

•

Join Date: Aug 2004

Posts: 369

Reputation: Thinka is an unknown quantity at this point

Solved Threads: 10

Thinka

Offline

Posting Whiz

do-while loop & other stuff

Jan 30th, 2007

Hi, I am new to Java, and have been trying to write a program that calculates the square root of a number using the Babylonian/Heron method. I have been able to make it work, largely due to a lot of help from a PhD student.
So yeah, what I'm trying to do now is to create a do-while loop so that a user chooses whether they want to exit the program or not.

So far i've got

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
 System.out.println("Press y to continue using the program or any other character to exit");
		s = stdin.read();
		System.out.println( );
		}
		while (s = "y"){
 System.out.println("Press y to continue using the program or any other character to exit");
		s = stdin.read();
		System.out.println( );
		}
		while (s = "y"){

Where s is the variable name of whatever the user's response is. I want to say if the user presses y, for the whole program to run again, and if they don't, for the program to terminate.

All help is appreciated, thanks guys.

P.S. the relevant java class files are attached.

Attached Files

	Root22.java (1.3 KB, 15 views)
	RootApproximator2.java (582 Bytes, 12 views)

Never approach a computer with the words "I'll just do this quickly..."

•

Join Date: Apr 2006

Posts: 353

Reputation: aniseed is an unknown quantity at this point

Solved Threads: 6

aniseed

Offline

Posting Whiz

Re: do-while loop & other stuff

Jan 30th, 2007

From your code:

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
 while (s = "n"){
 while (s = "n"){

This is wrong in two aspects:
1. You are trying to do an assignment operation instead of comparison.
2. Even if you want to compare Strings, you should be using the equals() method instead of ==

Javascript is not Java

•

Join Date: Aug 2004

Posts: 369

Reputation: Thinka is an unknown quantity at this point

Solved Threads: 10

Thinka

Offline

Posting Whiz

Re: do-while loop & other stuff

Jan 30th, 2007

Hey aniseed, i'm using Eclipse, and it doesn't seem to like me using "equals()".

It also has a problem with my reading in line, i've got

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
 s=stdin.read();
 s=stdin.read();

and it told me that it couldn't convert an integer to a character (which sounds reasonable enough!)
Any ideas as to how to make that a character reading in line?

Never approach a computer with the words "I'll just do this quickly..."

•

Join Date: Nov 2004

Posts: 6,143

Reputation: jwenting is just really nice

Solved Threads: 212

jwenting

Offline

duckman

Re: do-while loop & other stuff

Jan 30th, 2007

Eclipse likes equals a lot... What you're doing, comparing object references using ==, is a deadly sin almost universally (there are a very few scenarios where you want it, but those are so specific you can for now forget about them).

In general: NEVER use == to compare objects, it doesn't work (or rather it works perfectly, just not how you think it does).

As people are clearly allowed to attack me but I'm not allowed to defend myself, I no longer post to this site.