算法题（检查数字是否为回文） _数字平方根

本文概述

C++
Java
Python3
C#
PHP

给定一个整数N, 编写一个程序, 如果给定数字是回文, 则返回true, 否则返回false。
例子：

Input: N = 2002 Output: trueInput: N = 1234 Output: false

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方法：
解决这个问题的一个简单方法是，首先将n的数字进行逆序，然后将n的逆序与n进行比较。如果两者相同，则返回true，否则返回false。
下面是上述方法的实现：
C++

//C program to check whether a number //is Palindrome or not.#include < stdio.h> /* Iterative function to reverse digits of num*/ int reverseDigits( int num) { int rev_num = 0; while (num> 0) { rev_num = rev_num * 10 + num % 10; num = num /10; } return rev_num; }/* Function to check if n is Palindrome*/ int isPalindrome( int n) {//get the reverse of n int rev_n = reverseDigits(n); //Check if rev_n and n are same or not. if (rev_n == n) return 1; else return 0; }/*Driver program to test reversDigits*/ int main() { int n = 4562; printf ( "Is %d a Palindrome number? -> %s\n" , n, isPalindrome(n) == 1 ? "true" : "false" ); n = 2002; printf ( "Is %d a Palindrome number? -> %s\n" , n, isPalindrome(n) == 1 ? "true" : "false" ); return 0; }

Java

//Java program to check whether a number //is Palindrome or not.class GFG { /* Iterative function to reverse digits of num*/ static int reverseDigits( int num) { int rev_num = 0 ; while (num> 0 ) { rev_num = rev_num * 10 + num % 10 ; num = num /10 ; } return rev_num; }/* Function to check if n is Palindrome*/ static int isPalindrome( int n) {//get the reverse of n int rev_n = reverseDigits(n); //Check if rev_n and n are same or not. if (rev_n == n) return 1 ; else return 0 ; }/*Driver program to test reversDigits*/ public static voidmain(String []args) { int n = 4562 ; System.out.println( "Is" + n + "a Palindrome number? -> " + (isPalindrome(n) == 1 ? "true" : "false" )); n = 2002 ; System.out.println( "Is" + n + "a Palindrome number? -> " + (isPalindrome(n) == 1 ? "true" : "false" )); }}//This code is contributed //by Hritik Raj ( ihritik )

Python3

# Python3 program to check whether a # number is Palindrome or not. # Iterative function to reverse # digits of num def reverseDigits(num) : rev_num = 0 ; while (num> 0 ) : rev_num = rev_num * 10 + num % 10 num = num //10return rev_num # Function to check if n is Palindrome def isPalindrome(n) :# get the reverse of n rev_n = reverseDigits(n); # Check if rev_n and n are same or not. if (rev_n = = n) : return 1 else : return 0# Driver Code if __name__ = = "__main__" :n = 4562if isPalindrome(n) = = 1 : print ( "Is" , n, "a Palindrome number? -> " , True )else : print ( "Is" , n, "a Palindrome number? -> " , False )n = 2002if isPalindrome(n) = = 1 : print ( "Is" , n, "a Palindrome number? -> " , True )else : print ( "Is" , n, "a Palindrome number? -> " , False )# This code is contributed by Ryuga

//C# program to check whether a number //is Palindrome or not.using System; class GFG { /* Iterative function to reverse digits of num*/ static int reverseDigits( int num) { int rev_num = 0; while (num> 0) { rev_num = rev_num * 10 + num % 10; num = num /10; } return rev_num; }/* Function to check if n is Palindrome*/ static int isPalindrome( int n) {//get the reverse of n int rev_n = reverseDigits(n); //Check if rev_n and n are same or not. if (rev_n == n) return 1; else return 0; }/*Driver program to test reversDigits*/ public static voidMain() { int n = 4562; Console.WriteLine( "Is" + n + "a Palindrome number? -> " + (isPalindrome(n) == 1 ? "true" : "false" )); n = 2002; Console.WriteLine( "Is" + n + "a Palindrome number? -> " + (isPalindrome(n) == 1 ? "true" : "false" )); }}//This code is contributed //by Hritik Raj ( ihritik )

PHP

< ?php //PHP program to check whether a number //is Palindrome or not.//Iterative function to reverse //digits of num function reverseDigits( $num ) { $rev_num = 0; while ( $num> 0) { $rev_num = $rev_num * 10 + $num % 10; $num = $num /10; } return $rev_num ; }//Function to check if n is Palindrome function isPalindrome( $n ) {//get the reverse of n $rev_n = reverseDigits( $n ); //Check if rev_n and n are same or not. if ( $rev_n == $n ) return 1; else return 0; }//Driver Code $n = 4562; echo "Is " , $n , " a Palindrome number? -> " ; if (isPalindrome( $n ) == 1) echo "true" ; else echo "false" ; echo "\n" ; $n = 2002; echo "Is " , $n , " a Palindrome number? -> " ; if (isPalindrome(! $n )) echo "true" ; else echo "false" ; //This code is contributed by jit_t ?>

【算法题（检查数字是否为回文）】输出如下：