[intv] check if string is palindrome.

//Problem: Check if string is palindrome.

#include <iostream>
#include <string.h> //required for strlen
#include <cctype> //required if you want to use toupper.
using namespace std;

bool checkPalin(char *);

int main(){
  char *str1 = "Thi is not a palin";
  char *str2 = "I prefer Pi";
  char *str3 = "A Toyota! Race fast, safe car. A Toyota.";

  cout << str1 << "  ** " << (checkPalin(str1)?"is":"is not") << " a Palindrome" << endl;
  cout << str2 << "  ** " << (checkPalin(str2)?"is":"is not") << " a Palindrome" << endl;
  cout << str3 << "  ** " << (checkPalin(str3)?"is":"is not") << " a Palindrome" << endl;

}

bool checkPalin(char *a){
  char *startIdx, *endIdx;
  char x, y;

  //check if the string is null or contains a single character.

  startIdx = a;
  endIdx = &a[(strlen(a)-1)];

  while(startIdx < endIdx){
    x = toupper(*startIdx);
    if ((x < 0x41) || (x > 0x5a)){startIdx++; continue;}

    y = toupper(*endIdx);
    if ((y < 0x41) || (y > 0x5a)){endIdx--; continue;}

    if (x != y) {return 0;}
    startIdx++; endIdx--;
  }
    return 1;

}