# Solved: palindrome

Palindrome is a term used in various fields including mathematics, linguistics, and computer science to represent numbers, words, sentences, or sequences that read the same backward as forward. This fascinating property of mirror symmetry offers exciting challenges and scenarios in algorithm design and coding.

COBOL (Common Business-Oriented Language) is an industry-grade programming language that has been widely used for business and finance-related software development since the 1950s. One of the classical problems often solved in COBOL is the determination of whether a string is a palindrome or not.

IDENTIFICATION DIVISION.
PROGRAM-ID. PALINDROME.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 STRING-1 PIC A(20) VALUE ‘RADAR’.
01 STRING-2 REDEFINES STRING-1.
01 I PIC 9 COMP-3 VALUE 1.
01 J PIC 9 COMP-3 VALUE 20.
PROCEDURE DIVISION.
PALINDROME-CHECK.
PERFORM UNTIL I > J
IF STRING-1(I:1) NOT = STRING-2(J:1) THEN
DISPLAY “NOT PALINDROME”
STOP RUN
END-IF
SUBTRACT 1 FROM J
END-PERFORM.
DISPLAY “PALINDROME”.
STOP RUN.
END PROGRAM PALINDROME.

## Understanding the COBOL Code

This COBOL program, named PALINDROME, operates by comparing the first and last character of the string, and then moving inwards, comparing all other corresponding pairs of characters. If it encounters a pair of characters that do not match, it concludes the string is not a palindrome and terminates the program. But if all pairs of compared characters match, the program concludes the string is a palindrome.

## Involvement of Libraries and Functions

COBOL, unlike many modern programming languages, does not make extensive use of additional libraries or specialized functions. Its power comes from its straightforward syntax and powerful built-in operations and commands. In this case, basic arithmetic operations (add, subtract) and comparison functions (IF NOT =) as well as loop structures (PERFORM UNTIL) are what define the logic of the program.

## Similar Problems

There are several problems similar to checking palindrome strings. Reverse number problem, anagram problem, and palindromic number problem are among those similar to palindrome string problem.

To sum it up, solving palindrome problems in COBOL is a matter of creating an intelligent loop that traverses the string from both ends. While COBOL might not be as trendy in the current development world, its influence and use cases – and of course its ability to process tasks like this one – remain robust in many corporate settings. Even the simple palindrome string problem unveils the timeless charm of this language born in the time of punch-card computing.

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