Problem with Head/Tails program

[ameerulislam]

I just wrote head or tails program. The program is working when I'm putting heads but its giving me wrong message when I put Tails. I spent a lot of time behind it and I can't find the silly mistake that I made :(.


Please help me out..

Thanks

import java.util.Scanner;
public class problem3p14 {

	/**
	 * problem3.14
	 */
	public static void main(String[] args) {
		int usernumber=0;
		 System.out.println("Enter a guess (Head/ Tail): ");
		 Scanner input = new Scanner(System.in);                    // user input variable is a string input 
	     String answer = input.next();
	    
	     int number1 = (int)(System.currentTimeMillis() % 2);  
	    
	     if(answer=="Head"||answer=="head"){                        // converting Head into 0
	    	usernumber=0;
	    	 
	     }else if(answer=="Tail"||answer=="tail"){                 // converting Tail into 1
	    	 usernumber=1;
	     }
	      
	     if(number1==usernumber){                                   //if matched get into this one
	    	 
	    	 if(usernumber==0){
	    		 System.out.println("You Are Correct Its Heads");
	    	 }else if (usernumber==1) {
	    		 System.out.println("You Are Correct Its Tails");
	    	 }	    	 
	     }else{                                                     //if not matched get into this one
	    	 if(usernumber==0){
	    		 System.out.println("Oops! You got it wrong it was Tails");
	    	 }else if (usernumber==1) {
	    		 System.out.println("Oops! You got it wrong it was Head");
	    	 }
	     }
	     input.close();
}
}

[DrummondAW]

I think you need to do some debugging. Your if statements that compare the initial input and set your usernumber variable weren't working. To figure this out you simply set usernumber = 10 initially and then see if the value changes by executing a System.out.println. Try comparing your strings as such...

if(answer.equals("Head")||answer.equals("head"))

I'm still new to Java and I'm hoping someone can explain why the code doesn't work if you use == to compare the strings.

Edit: found a good article explaining this problem

[ameerulislam]

yes I have checked that, there is something wrong with the initialization. I tried putting 5 and program got broken actually. I forgot to mention that.

[DrummondAW]

It should be working now, correct?

[sibernewf]

Just another small tip. instead of:
if(answer.equals("Head")||answer.equals("head"))


try:

if(answer.equalsIgnoreCase("head"))

instead. then you dont need to do the || check.

Good luck

[ameerulislam]

It should be working now, correct?

Guys its working with .equals and .equalsIgnoreCase! Strange really.. why this one didn't work with == .

Thanks both of you.

[Tolls]

Strings are objects.
You compare them with equals().
'==' simply checks whether it is referring to the exact same object on the heap.

[ameerulislam]

if strings are objects, numbers such as are int double are what?

[DarrylBurke]

Primitives.

db

[DarrylBurke]

To further clarify; variable references of a primitive type actually hold the value assigned to them. So if two int variables a and b both contain the value 5

int a = 5;
int b = 5;

it follows that the two variables have an equal content and this evaluates to true:

a == b

Variables of a reference type -- those that refer to obejcts -- hold a reference to the assigned value. Thus for

String a = new String("Hello");
String b = new String("Hello");

the two variables hold different references and this evaluates to false:

a == b

The equals(...) method passes a reference to one String to the other String to determine its equality; like any other method, the equals(...) method executes the program flow determined by code within the method and returns a value. To see what String#equals(...) really does, take a look at the source of java.lang.String which you can find in the src.zip file in your JDK installation folder.

db