Can anyone explain me this code?

Question

1.00/5 (2 votes)

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int result line is most confusing

What I have tried:

Java

import java.util.stream.IntStream;

public class Palindrome {
    public static void main(String[] args) {
        String num = "1234321";
        int pos = num.length()-1;
        int middle = num.length()/2;
        int result = IntStream.rangeClosed(0, middle).anyMatch(i -> num.charAt(i) != num.charAt(pos - i)) ? 0 : 1;
        System.out.println(result!=1?"false":"true");



        }

Posted 14-Jun-22 22:59pm

Shashi Kumar Jun2022

Updated 15-Jun-22 0:31am

CPallini

v2

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OriginalGriff · Answer 1 · 2022-06-14T23:09:00

it's just calling a method called rangeClosed, then using the result of that to call a method called anyMatch with returns true if the condition evaluates to true on one or more of the items in the collection.
That true or false result is used to select 0 if it's true, and 1 if it's false

Break it down into separate lines which store the result and it's more obviuous to beginners:

Java

int result;
var range = IntStream.rangeClosed(0, middle);
var foundAMatch = range.anyMatch(i -> num.charAt(i) != num.charAt(pos - i));
if (foundAMatch) {
   result =  0;
   }
else {
   result = 1;
   }

CPallini · Answer 2 · 2022-06-15T00:31:00

Solution 2

Note, the posted code is equivalent to the more expicit (and possibly cleaner))

Java

public static void main(String[] args)
{
  String num = "12344321";
  int last = num.length()-1;
  int middle = last/2;

  int i;
  for ( i = 0; i < middle; ++i)
  {
    if (num.charAt(i) != num.charAt(last-i))
    {
      break;
    }
  }
  System.out.printf("%b\n", (i == middle));
}

Posted 15-Jun-22 0:31am

CPallini

Comments

Patrice T 15-Jun-22 7:24am

+5

CPallini 15-Jun-22 7:28am

Thank you.

Can anyone explain me this code?

2 solutions

Solution 1

Solution 2

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