efficient program for checking a string is palindrome or not in cpp code example

Example 1: check if a string is palindrome cpp

// Check whether the string is a palindrome or not.
#include <bits/stdc++.h>

using namespace std;

int main(){
    string s;
    cin >> s;
    
    int l = 0;
    int h = s.length()-1;

    while(h > l){
        if(s[l++] != s[h--]){
            cout << "Not a palindrome" << endl;
            return 0;
        }
    }
    cout << "Is a palindrome" << endl;
    return 0;

}

Example 2: Write a function that tests whether a string is a palindrome

def palindrome_check(string):
    string = list(string)
    tmp = []
    #remove any spaces
    for x in range(0, len(string)):
        if(string[x] != " "):
            tmp.append(string[x].lower())
    
            
    #now reverse the string
    array1 = []
    i = 0
    j = len(tmp)-1

    while(i < len(tmp)):
        array1.append(tmp[j])
        i += 1
        j -= 1

    #check if array1 is equal to the string
    counter = 0
    for x in range(0, len(tmp)):
        if(tmp[x] == array1[x]):
            counter += 1

    #if the counter is equal to the length of the string then the word
    #is the same
    if(counter == len(tmp)):
        return True
    
    return False

Example 3: Write a program to check whether inputted string is palindrome or not.

#include <stdio.h>
#include <string.h>
 
int main()
{
    char s[1000];  
    int i,n,c=0;
 
    printf("Enter  the string : ");
    gets(s);
    n=strlen(s);
 
    for(i=0;i<n/2;i++)  
    {
    	if(s[i]==s[n-i-1])
    	c++;
 
 	}
 	if(c==i)
 	    printf("string is palindrome");
    else
        printf("string is not palindrome");
 
 	 
     
    return 0;
}