Java if-else control statements

Question

I'm newbie in java and i need some help.I created a class;

public class asdd {
    String name;
    String Lastname;
    int age;

    public asdd(String value1,String value2,int value3){

        this.name=value1;
        this.Lastname=value2;
        this.age=value3;
    }

}

Then i wrote some code to do practic but i faced a problem with if control statement in below. Although input is "mike" my program bypasses if and runs else statement. Thanks.

import java.util.Scanner;

public class dd {

    public static void main(String[] arguments){

      asdd person=new asdd("mike","angel",21);
      Scanner input= new Scanner(System.in);
      String control=input.nextLine();

      if (control==person.name)
        System.out.println("hi baby");
      else
        System.out.println(person.Lastname);

   }    
}

Also i'm getting error after run program.

Hello and welcome to StackOverflow. When editing your next question, click on the edit help link on the top right of the edit window to learn how to use edit features of this site, including how to format your code. — Hovercraft Full Of Eels, Feb 22 '14 at 14:45

score 4 · Accepted Answer · answered Feb 22 '14 at 14:43

As a quick search on this site would have quickly revealed, you should use the equals() method of String objects instead of ==. The former compares strings lexicographically, whereas the latter compares object references. So you want:

if (control.equals(person.name))

instead of:

if (control==person.name)

As an aside, class names should start with a capital letter, not lower case. And you should also explicitly specify the visibility of your Asdf class' variables: specifically, it's good practice to access them only through getters, as opposed to directly as you are doing.

score 1 · Answer 2 · answered Feb 22 '14 at 14:43

1

Use String.equals() to compare String literals in Java, not == Change your code like this

if(control.equals(person.name))

answered Feb 22 '14 at 14:43

Keerthivasan

12,760
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score 1 · Answer 3 · edited May 23 '17 at 12:07

1

Sadly, java isn't javascript, or numerous other languages that use == sensibly.

== compares identity - true only if the two objects are the same object.

.equals() should be used to compare values:

if (control.equals(person.name))

It is generally considered a "mistake" that java doesn't use == as you expected it to work. For some other java "mistakes", see this answer.

edited May 23 '17 at 12:07

Community

1
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answered Feb 22 '14 at 14:45

Bohemian

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score 0 · Answer 4 · answered Feb 22 '14 at 14:46

0

The == operator is for numeric values. For strings use the .equals method:

    String s1 = "value", s2 = "value";
    if (s1.equals(s2)) {
      // do your code here
    }

answered Feb 22 '14 at 14:46

Froxx

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Java if-else control statements

4 Answers4