Need help with my code

**JakeEdwards27** · 10-02-2011, 06:51 PM

Hey guys,

Im completely new to coding. I literally started about 3 weeks ago. I haven't done computer science yet so bear with me :)

Java Code:

import java.util.Scanner;

public class MainClass {
	public static void main(String[] args){
	
		Scanner sc = new Scanner (System.in);
		boolean input = sc.nextLine() != null;
		System.out.println(input);		
			if (input = "Hello my friend" != null){
					System.out.println("Ahh, hello there!");
			
			
			
			}
		
	}
}

This code works but i dont know why.. A bunch of errors showed up before and told me to add the two "!= null". Also I had the variable "input" as a String instead of a Boolean. When i tried to switch it to a boolean before the two "!= null", it said i wasn't aloud to do that.. Can anyone explain this to me? Any help would be appreciated.

**sunde887** · 10-02-2011, 07:10 PM

sc.nextLine() returns a string, not a boolean. What happens if someone types in "blah", how can that be a boolean value(true/false). If you intend to get a string variable, store it in a String variable. In your code, input is a boolean, "Hello my friend" != null returns true as long as the string is not null. If this makes sense--good. If not ask me to clarify, and I will.

**Norm** · 10-02-2011, 07:15 PM

boolean input = sc.nextLine() != null;

Instead of trying to do two things in one statement, break this statement into two simple statements.
1) get the input
2) test it

**JakeEdwards27** · 10-02-2011, 08:03 PM

Thanks for the help guys :) i changed the variable to a string and then it underlines "input = "Hello my friend" and says i cannot covert it
from a string to a boolean. Can i just simply not have an if statement for a String variable? Is there anyway to go around that? For example, i want the console to respond to the user if he says a certain thing. Sorry if im not making sense.

**sunde887** · 10-02-2011, 08:05 PM

Check out the .equals(Object o) method. String (Java Platform SE 6)

**Norm** · 10-02-2011, 08:08 PM

Can you post the code with the problem?

The following statement has a boolean on the left and a String on the right

Java Code:

boolean input = "Hello my friend";

That doesn't work. You need
either a String variable on the left
or a boolean expression on the right.

**JakeEdwards27** · 10-02-2011, 08:13 PM

Java Code:

import java.util.Scanner;

public class MainClass {
	public static void main(String[] args){
	
		Scanner sc = new Scanner (System.in);
		String input = sc.nextLine();
		System.out.println(input);		
			if ([U]input = "Hello my friend"[/U]){
					System.out.println("Ahh, hello there!");
			
			
			
			}
		
	}
}

**sunde887** · 10-02-2011, 08:14 PM

When posting code, please use code tags: [code] YOUR CODE HERE [/code]

Also, '=' is an assignment operator, comparisons is done with '==' and strings need to be compared with .equals(Object o)

**JakeEdwards27** · 10-02-2011, 08:16 PM

Is there something different besides a string or boolean that i can use? I looked at the .equals (Object o) method. I dont really understand that. It said it was a "superclass" or something...

**JakeEdwards27** · 10-02-2011, 08:17 PM

oh sorry about that :/ i was wondering how to do that haha

**JakeEdwards27** · 10-02-2011, 08:19 PM

Ohhhh hold on i think i know how to fix it..

**JakeEdwards27** · 10-02-2011, 08:21 PM

Alright i fixed it all i had to do was change it from '=' to '=='. Thanks guys!

**sunde887** · 10-02-2011, 08:24 PM

That is still actually incorrect. For primitives it is fine to use '==' but for strings this compares references--which is not what you want. Instead use equals.

Java Code: