Java/Data Type/String equal
Check string for equality
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public class Main {
public static void main(String[] args) { String s1 = "Hello World"; String s2 = new String("Hello World"); if (s1.equals(s2)) { System.out.println("String is equal"); } else { System.out.println("String is unequal"); } if (s1 == s2) { System.out.println("String is equal"); } else { System.out.println("String is unequal"); } }
}
</source>
Determine whether a string is a palindrome?
<source lang="java">
public class Main {
static boolean isPalindrome(String text) { System.out.println("Original text = " + text); String reverse = new StringBuilder(text).reverse().toString(); System.out.println("Reverse text = " + reverse); return text.equalsIgnoreCase(reverse); } public static void main(String[] args) { String text = "Sator Arepo Tenet Opera Rotas"; System.out.println("Is Palindrom: " + isPalindrome(text)); }
}
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String: equal
<source lang="java">
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002. * All rights reserved. Software written by Ian F. Darwin and others. * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $ * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS"" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee * cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s, * pioneering role in inventing and promulgating (and standardizing) the Java * language and environment is gratefully acknowledged. * * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for * inventing predecessor languages C and C++ is also gratefully acknowledged. */
public class Equality {
public static void main(String[] args) { new Equality().run(); } public void run() { String x = "hello"; String y = "hello"; // Assuming Equality uses a String constant, this prints true,true compare(x, y); // A "new String" is uniquely created, so this prints false, true compare(x, new String(y)); // The substring operator creates a new String, prints false, true compare(x, "hello world".substring(0, 5)); // The intern() operator returns a string from the pool of unique // strings, so this should print true, true. compare(x, new String(x).intern()); } public void compare(String s1, String s2) { System.out.print("==: "); System.out.println(s1 == s2); System.out.println(".equals():" + s1.equals(s2)); System.out.println(); }
}
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