Java else if with strings not working - Scanner(System.in);

Question

I am very new in java and to programming overall. Recently, I have started an IA mock-up program, but my else-if part of code is not showing in the terminal, I suppose. However, the if and the else statements do seem to work perfectly.
I'd appreciate any help you can provide.
Sorry for my lackluster English and my inaccurate words.

import java.util.Scanner;
public class IA
{
    public static void main(String []args){

       Scanner lector= new Scanner(System.in);

       System.out.println("Di algo");
       String input = lector.next();    

       if (input.equals ("Hola") || input.equals("hola") || input.equals("ola")){
            System.out.println("Hola, humano");
       }else if (input==("quien eres")){
            System.out.println("Una pobre ilusión de inteligencia artificial");
       }else{
        System.out.println("Adiós");
       }
   }
}

Write the code here, properly formatted. Translate to English to the best of your ability. (By "here" I mean "edit your question", not add as a comment). — Marko Topolnik, Sep 02 '16 at 14:03
Define 'not working'. Is there an error message or is the output not what you expected? — bradimus, Sep 02 '16 at 14:04
check your input string. next() does not consider strings after spaces. And `most imporatntly don't attach image, write code.` — Shahid, Sep 02 '16 at 14:05
I'll give you a stab-in-the-dark hint: use `nextLine()` instead of `next()` because `quien heres` are two tokens as far as `next` is concerned. — Marko Topolnik, Sep 02 '16 at 14:06
Firstly, there shouldn't be spaces between the function and its parameters, but thats more stylistic — Zachary Weixelbaum, Sep 02 '16 at 14:07

Bahadir Tasdemir · Accepted Answer · 2016-09-02T15:35:43.700

2

What you are missing is not checking the input value. First check the input value...:

System.out.println(input);

...and see if the value is ok. Then you can say if your "if-else" component is working or not.

Also delete the gap @ input.equals ("Hola"). it must be input.equals("Hola")

Addition: You cannot use == operator for Strings in Java. You can use var.equals("something") to check if variable var equals to "something".

Addition 2: You must use scanner.nextLine() to get typed string completely instead of using scanner.next() because next() gets the next WORD.

And here is your working code:

edited Sep 02 '16 at 15:35

answered Sep 02 '16 at 14:06

Bahadir Tasdemir

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A method invocation works just as well with or without a space before the brackets. It *should* be `input.equals("Hola")` according to most style guides, but "must" implies that it won't work otherwise. – jsheeran Sep 02 '16 at 14:11
Thank you very much @jsheeran you are right but here, I am trying to solve the problem and it is not as you say, it is "DEPENDS ON THE COMPILER" ;) – Bahadir Tasdemir Sep 02 '16 at 14:13
and where should I add that line of code? sorry – Alex Vilchis Sep 02 '16 at 14:17
As you see in this link: http://ideone.com/yitvbO you must add it just before your if-else structure. Could you please mark as the right answer? – Bahadir Tasdemir Sep 02 '16 at 14:24
I changed the code as you asked, but the issue still persists. I get "Adiós" displayed. – Alex Vilchis Sep 02 '16 at 15:04
But are the values correct? Because I copied and pasted your code and given the input as "Hola" and worked great. You can see code, input and output in the link I provided for you: http://ideone.com/yitvbO – Bahadir Tasdemir Sep 02 '16 at 15:08
Check the stdin and stdout in the bottom of the page under the code. – Bahadir Tasdemir Sep 02 '16 at 15:09
the if else component is not working. It goes directly to the else compoment – Alex Vilchis Sep 02 '16 at 15:12
hola works, but quien eres doesn't – Alex Vilchis Sep 02 '16 at 15:13
this is ignored – Alex Vilchis Sep 02 '16 at 15:15
else if (input==("quien eres")){ System.out.println("Una pobre ilusión de inteligencia artificial"); } – Alex Vilchis Sep 02 '16 at 15:20
So I think you won't see the "quien eres" in the System.out.println(input). You must see first "quien" and later "eres" in the values which are not suitable for the if-else code part because scanner.next() only gets the next WORD. To provide it, you must use scanner.nextLine();. Try it, you will see it will work. – Bahadir Tasdemir Sep 02 '16 at 15:20
And also, you must use input.equals("quien eres"). Because operator == is not working for Strings in Java. – Bahadir Tasdemir Sep 02 '16 at 15:24
Check this is working now http://ideone.com/yitvbO – Bahadir Tasdemir Sep 02 '16 at 15:25
Thanks. It works. Apologies for my ineptutude. – Alex Vilchis Sep 02 '16 at 15:28
No problem, you know nobody is a master and everybody understands in a different way as Einstein indicated years ago and people still do not understand :) Cheers! – Bahadir Tasdemir Sep 02 '16 at 15:33
Hey, quick question. How can I make it so that my program can recieve more messages wihtout ending? Like a chatbot. – Alex Vilchis Sep 02 '16 at 15:42
Quick answer: "No quick questions" ;) – Bahadir Tasdemir Sep 02 '16 at 15:42
Sorry, I did not understand – Alex Vilchis Sep 02 '16 at 15:54

score 2 · Answer 2 · answered Sep 02 '16 at 14:07

2

You'll need to change the delimiter of the Scanner if you want it to pick up tokens that contain spaces. Because the default delimiter is a space, if it encounters quien eres, next() will be quien.

answered Sep 02 '16 at 14:07

jsheeran

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Java else if with strings not working - Scanner(System.in);

2 Answers2