This question already has answers here:
How do I compare strings in Java?
(23 answers)
Closed 8 years ago.
Below is the code:
package com.myprograms.test;
import java.util.Scanner;
public class MyProgram {
public static void main(String[] args) {
Scanner sIn = new Scanner(System.in);
String name = "";
System.out.print("Enter the name:");
name = sIn.next();
if (name.equals("somename")) {
System.out.println("Success - Case 1");
} else {
System.out.println("Failed - Case 1");
}
if (name == "somename") {
System.out.println("Success - Case 2");
} else {
System.out.println("Failed - Case 2");
}
sIn.close();
}
}
Below is the output:
Enter the name: somename
Success - Case 1
Failed - Case 2
Here is the question:
Why one input behaves differently for the same condition in Java? Is it Java error?
"Java Error" - Really..??
This was explained many times, anyway here is a small explanation:
While comparing string in Java, use String.equals() or String.equlasIgnoreCase() methods.
Using == operator, compares the address.
While using equals() or equalsIgnoreCase() method compares the contents of the Strings.
Here is a good explanation (read "Meet Jorman" example):
An observation: You can close the Scanner after getting the inputs, instead of last line of the program, for better resource management.
Related
This question already has answers here:
How do I compare strings in Java?
(23 answers)
Closed 4 years ago.
I have made a JAVA program where I have initialized a 1-D String array. I have used for loop to search any inputted String if it exists in the array(Scanner Class).
Here is the source code :-
import java.util.*;
class search
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
System.out.println("Enter the name to search :-");
String s=sc.nextLine();
String array[]={"Roger","John","Ford","Randy","Bacon","Francis"};
int flag=0,i;
for(i=0;i<6;i++)
{
if(s==array[i])
{
flag=1;
break;
}
}
if(flag==1)
System.out.println("The name "+s+" Exists");
else
System.out.println("The name "+s+" does not Exists");
}
}
The class even compiles successfully, but when I enter a valid string(say- Roger), the output is The name Roger does not Exists.
Please help me out with this issue, and for this I shall be grateful to you.
Thanking You,
J.K. Jha,
01.09.2018.
You are confusing == and equals
Since String is an object == just checks for if the references are same instead of actual contents
You should use String.equals() instead
Changes your if condition
for(i=0;i<6;i++)
{
if(s.equals(array[i]))
{
flag=1;
break;
}
}
This question already has answers here:
How do I compare strings in Java?
(23 answers)
How can I read input from the console using the Scanner class in Java?
(17 answers)
Closed 5 years ago.
I just started reading about JAVA and I want to make a little program that when using Scanner is I type "yes", "no" or just something random I will get different messages.The problem if with the lines:
if (LEAVE == "yes") {
System.out.println("ok, lets go");
if (LEAVE == "no") {
System.out.println("you dont have a choice");
} else {
System.out.println("it's a yes or no question");
I receive the error : Operator "==" cannot be applied to "java.util.scanner", "java.lang.String". I saw on a site that it would be better if I replaced "==" with .equals,but I still get an error..
Help please :S
Code below:
package com.company;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner LEAVE = new Scanner(System.in);
System.out.println("do you want to answer this test?");
LEAVE.next();
System.out.println("first q: would you leave the hotel?");
LEAVE.next();
if (LEAVE == "yes") {
System.out.println("ok, lets go");
}
LEAVE.nextLine();
if (LEAVE == "no") {
System.out.println("you dont have a choice");
LEAVE.nextLine();
} else {
System.out.println("it's a yes or no question");
}
}}
Scanner LEAVE = new Scanner(System.in);
Implies that LEAVE is Scanner class object. Right.
if (LEAVE == "yes")
You are comparing the Scanner type object with String type object and hence you are getting
Operator "==" cannot be applied to "java.util.scanner", "java.lang.String"
Now consider
LEAVE.next();
you are calling next() which belongs to LEAVE object. That next function is suppose to read a value and return that to you. So what you do is receive this value in another String type object and then further compare it to 'YES' or 'NO' or whatever.
String response = LEAVE.next()
if(response.equalsIgnoreCase("yes")){
// do something
}else if(response.equalsIgnoreCase("no")){
// do something else
}
More about Scanner class
GeeksForGeeks
This question already has answers here:
How do I compare strings in Java?
(23 answers)
Closed 7 years ago.
So I have this executable jar file with a username and password and runs but value doesn't ever continue correctly.
Here is an example:
public static void main(String[] args) {
System.out.println("Hello. I am a program created by Moocow9m. What is your name?");
InputStream stream = System.in;
Scanner scanner = new Scanner(stream);
String input = scanner.next();
if (input == "armystich"){
System.out.println("Welcome CODE NAME: ArmyStich!");
scanner.close();
}
else {
System.out.println("Hello " + input + ". Nice to meet you.");
scanner.close();
}
}
}
All would work except it would always return to else. Please help.
if (input == "armystich"){
The above checks reference equality. To check for value equality, using the equals method
if ( input.equals("armystich") ){
See How do I compare strings in Java?
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
How do I compare strings in Java?
I'm working on a small program that asks for your name using a Scanner. If you enter blankstring, then I would like the console to display a message.
Here's what I tried doing:
import java.util.Scanner;
public class Adventure
{
public static void main(String[] args)
{
Scanner myScan = new Scanner (System.in);
System.out.println("What's your name?");
String name = myScan.nextLine();
while (!(name == "")) //Always returns false.
{
System.out.println("That's not your name. Please try again.");
name = myScan.nextLine();
}
System.out.println("It's a pleasure to meet you, " + name + ".");
}
}
The code never enters the while loop. Why?
Change your condition to:
while(!name.equals("")) {
or as suggested below by m0skit0:
while(!name.isEmpty()) {
See also
why equals() method when we have == operator?
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
How do I compare strings in Java?
What am I doing wrong? After I compile and run the program, I type in my input and no matter what it is, the program always takes it as an incorrect input and says I'm wrong, here:
import java.util.Scanner;
public class mena3 {
public static void main(String[] args) {
Scanner user_input = new Scanner(System.in);
String Capitol;
System.out.print("Enter the capitol of Morocco: ");
Capitol = user_input.next();
if(Capitol == "Rabat") {
System.out.println("Good Job!");
}
else {
System.out.println("That is incorrect");
}
}
}
And after I put in Rabat, it says That is incorrect. If I put in l, it says That is incorrect. Why can't I win?
Don't compare Strings using ==. Use the equals(...) or the equalsIgnoreCase(...) method instead. Understand that == checks if the two objects are the same which is not what you're interested in. The methods on the other hand check if the two Strings have the same characters in the same order, and that's what matters here. So instead of
if (fu == "bar") {
// do something
}
do,
if ("bar".equals(fu)) {
// do something
}
or,
if ("bar".equalsIgnoreCase(fu)) {
// do something
}
Voting to close this question as it's only been asked and answered umpteen million times on this site.
One of the most common mistakes in java. String require a .equals() rather than an ==.
Wrong:
if (str == "foo") {
}
Right:
if ("foo".equals(str)) { // done in this order to avoid NPE
}
Your code is perfect, only your comparison method is wrong. All other languages treats == as comparison operator. But in case of Java it is little bit tricky. Here in Java == is taken as comparison operator for objects, not a string variable.
So, to compare two Strings you have a method called `.equals() which is from String class it self.
hence you need to change your code accordingly,
import java.util.Scanner;
public class mena3
{
public static void main(String[] args)
{
Scanner user_input = new Scanner(System.in);
String Capitol;
System.out.print("Enter the capitol of Morocco: ");
Capitol = user_input.next();
// if(Capitol == "Rabat") // your previous code
if(Capitol .equals ( "Rabat") ) // new updated comparison code
{
System.out.println("Good Job!");
}
else
{
System.out.println("That is incorrect");
}
}
}