java simple palindrome algorithm

Algorithm requires

Write a program to determine whether a string is "palindrome." Palindrome sequence: character string coincides with a front to rear from the back (centrosymmetric).

Algorithm thinking

First, the string around two aliquots, followed symmetrical characters are the same for each comparison

Code

import java.util.Scanner;

public class Palindrome {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (!sc.hasNext("###")) {
            String data = sc.next();
            if (isPalin(data)) {
                System.out.println("yes");
            } else {
                System.out.println("no");
            }
        }
        sc.close();
    }

    public static boolean isPalin(String data) {
        int len = data.length();
        for (int i = 0; i < len/2; i++) {
            if (data.charAt(i) != data.charAt(len-1-i)) {
                return false;
            }
        }
        return true;
    }

}

Test case

abc
no
qwq
yes
abcdcba
yes

tips

1, equals and ==

== operator execution rules

If the basic data types of variables, their value is more
If it is a reference type variable, then compare objects they point to address

equals method execution rules

It equals the original method, the address comparison reference type variable points of the object
String, Date, etc. based on the equals method has been rewritten at this time compares the contents of the object pointed to

ps: equals method is a method in the base class Object, to compare whether two object references are equal, i.e., whether the same object

Inquiry: Talking in Java equals and == https://www.cnblogs.com/dolphin0520/p/3592500.html

2, sc.hasNext () implement multiple sets of input

!sc.hasNext("###")  // 匹配 ### 返回true，然后取非运算。即以 ### 作为停止输入的命令

hasNext () and next () effect in fact is the same, the system will wait for the next input character, but returns a different value, hasNext () returns true, next () returns the character entered. If hasNext (returns true) when the next parameter is the character and the parameter value will match.

Inquiry: hasNext Scanner's () method https://blog.csdn.net/gao_zhennan/article/details/80562548