Check if string is palindrome in objective c

Question

I\'m trying to check if a string is palindrome or not using objective c. I\'m new to programming without any experience in other programming languages so bear with me please

Answer 1

@import Foundation;

BOOL isPalindrome(NSString * str)
{
    if (!str || str.length == 0) return NO;
    if (str.length == 1) return YES;
    for(unsigned i = 0; i < str.length / 2; ++i)
        if ([str characterAtIndex:i] != [str characterAtIndex:str.length - i - 1]) return NO;
    return YES;
}

int main() {
    @autoreleasepool {
        NSLog(@"%s", isPalindrome(@"applelppa") ? "YES" : "NO");
    } return 0;
}

Answer 2

var str: NSString = "123321"
var length = str.length
var isPalindrome = true

for index in 0...length/2{
    if(str.characterAtIndex(index) != str.characterAtIndex(length-1 - index)){
        print("\(index )not palindrome")
        isPalindrome = false
        break
    }
}

print("is palindrome: \(isPalindrome)")

Answer 3

-(BOOL)checkPalindromeNumber:(int)number{
    int originalNumber,reversedNumber = 0,remainder;
    originalNumber=number;
    while (number!=0) {
        remainder=number%10;
        reversedNumber=(reversedNumber*10)+remainder;
        number=number/10;
    }

    if (reversedNumber==originalNumber) {
        NSLog(@"%d is Palindrome Number",originalNumber);

        return YES;
    }
    else{
        NSLog(@"%d is Not Palindrome Number",originalNumber);
        return NO;

    }
}

Answer 4

As it seems there's no answer yet that handles composed character sequences correctly I'm adding my two cents:

NSString *testString = @"\u00E0 a\u0300"; // "à à"

NSMutableArray *logicalCharacters = [NSMutableArray array];
[testString enumerateSubstringsInRange:(NSRange){0, [testString length]}
                               options:NSStringEnumerationByComposedCharacterSequences
                            usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop)
{
    [logicalCharacters addObject:substring];
}];

NSUInteger count = [logicalCharacters count];
BOOL isPalindrome = YES;
for (NSUInteger idx = 0; idx < count / 2; ++idx) {
    NSString *a = logicalCharacters[idx];
    NSString *b = logicalCharacters[count - idx - 1];
    if ([a localizedCaseInsensitiveCompare:b] != NSOrderedSame) {
        isPalindrome = NO;
        break;
    }
}

NSLog(@"isPalindrome: %d", isPalindrome);

This splits the string into an array of logical characters (elements of a string that a normal user would call a "character").