Check if a string is palindrome

Question

I need to create a program that allows a user to input a string and my program will check to see if that string they entered is a palindrome  word that can be read the same backwards as it can forwards

User · Answer

I m no c   guy  but you should be able to get the gist from this   public static string Reverse string s        if  s    null    s Length  lt  2            return s             int length   s Length      int loop    length  gt  gt  1    1      int j      char   chars   new char length       for  int i   0  i  lt  loop  i              j   length - i - 1          chars i    s j           chars j    s i             return new string chars

User · Answer

bool IsPalindrome const char  psz        int i   0      int j       if   psz    NULL      psz 0       0                  return false             j   strlen psz  - 1      while  i  lt  j                if  psz i     psz j                         return false                    i            j--            return true          STL string version   bool IsPalindrome const string amp  str        if  str empty            return false       int i   0                    first characters     int j   str length   - 1     last character      while  i  lt  j                if  str i     str j                         return false                    i            j--            return true

User · Answer

Note that reversing the whole string  either with the rbegin   rend   range constructor or with std  reverse  and comparing it with the input would perform unnecessary work   It s sufficient to compare the first half of the string with the latter half  in reverse    include  lt string gt   include  lt algorithm gt   include  lt iostream gt  int main         std  string s      std  cin  gt  gt  s      if  equal s begin    s begin     s size   2  s rbegin              std  cout  lt  lt   is a palindrome  n       else         std  cout  lt  lt   is NOT a palindrome  n       demo  http   ideone com mq8qK

User · Answer

Just compare the string with itself reversed   string input   cout  lt  lt   Please enter a string     cin  gt  gt  input   if  input    string input rbegin    input rend           cout  lt  lt  input  lt  lt    is a palindrome       This constructor of string takes a beginning and ending iterator and creates the string from the characters between those two iterators  Since rbegin   is the end of the string and incrementing it goes backwards through the string  the string we create will have the characters of input added to it in reverse  reversing the string   Then you just compare it to input and if they are equal  it is a palindrome   This does not take into account capitalisation or spaces  so you ll have to improve on it yourself

User · Answer

The below C   function checks for a palindrome and     returns true if it is a palindrome and returns false otherwise  bool checkPalindrome   string s            This calculates the length of the string      int n   s length            the for loop iterates until the first half of the string        and checks first element with the last element         second element with second last element and so on         if those two characters are not same  hence we return false because        this string is not a palindrome       for   int i   0  i  lt   n 2  i                    if   s i     s n-1-i                return false                    if the above for loop executes completely           this implies that the string is palindrome          hence we return true and exit      return true

User · Answer

Reverse the string and check if original string and reverse are same or not

[c++] Check if a string is palindrome

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