#include <string>
#include <iostream>

using namespace std;

//delcare function prototypes
void getSentence(string&);
bool isPal(string);
void getStrings(string&, string&);
int searchReplace(string&, string, string);
void printInfo(int, string, string, string);

int main()
{
   //define variables
   char whatDo;
   string input1, search, replace;
   int times;

   //loop until exit
   while(whatDo != 'e')
   {
      //ask user what they would like to do
      cout << "Would you like to check if a (p)alindrome, (s)earch/replace, or (e)xit?: ";
      cin >> whatDo;

      //determine what to do based on user input
      if(whatDo == 'p')
      {
	 //get the sentence wanted
	 getSentence(input1);

	 //determine if it was a palindrome and print if it is
	 if(isPal(input1) == true)
	 {
	    cout << "You entered a palindrome!" << endl; 
	 }
	 else
	 {
	    cout << "The string you entered is not a palindrome :( " << endl;		
	 }
      }
      else if(whatDo == 's')
      {
	 //get the initial string
	 getSentence(input1);
	 //get the strings the user wants to use
	 getStrings(search, replace);

	 //search and replace the stuff
	 times = searchReplace(input1, search, replace);

	 //print out the info about the funtion
	 printInfo(times, input1, search, replace); 
      }
      else if(whatDo == 'e')
      {
	 return 0;
      }
      else
      {
	 cout << "Bad input, enter new request" << endl;
      }
   }
}

//get the sentence the user would like to use
//preconditions: user has selected to either check a palindrome or search and replace
//postconditions: the program has a string to use
//return:nothing
void getSentence(string &usIn)
{
   //ask the user for the sentence they want to search in 
   cin.ignore();
   cout << "Enter the sentence: ";
   getline(cin, usIn);
}

//check to see if the word entered is a palindrom
//preconditions: user has entered a string to be checked
//postconditions: the program has checked if the string is a palindrom and returns accordingly
//return: true or false for whether string is a palindrome
bool isPal(string input)
{
   //check the parts of the string starting at both ends and moving inwards
   for(int j=0; j < (input.size()/2); j++)
   {
      if(input[j] != input[input.size()-(j+1)])
      {
	 return false;
      }
   }

   //if it makes it through that then it is a palindrome
   return true; 
}

//input the word we want to search for and replace
//preconditions: user has selected to search and replace and has entered a sentence
//postconditions: the program has the words to search and replace
//reutn: nothing 
void getStrings(string &sea, string &rep)
{
   cout << "Enter the word you want to search for: ";
   cin >> sea;

   cout << "Enter the word you want to replace it with: ";
   cin >> rep;
}

//replace the word with the other one
//preconditions: user has inputed a sentence, and words to search and replace
//postcondition: words have been replaced in the string provided
//return: the number of times the work was replaced 
int searchReplace(string &usIn, string searchWord, string repWord)
{
   //initialize local variables
   int count = 0;

   //while there is an instance of the word in the string, do some stuff
   while(usIn.find(searchWord) != -1)
   {
      //replace searchWord.size # of characters starting at usIn.find() with repword 
      usIn.replace(usIn.find(searchWord), searchWord.size(), repWord);

      //increment how many times word is replaced 
      count ++;
   }

   //print number of times word repace
   return count;
}

//prints out the info on the search and replace
//preconditions: the program has replaced the words in the sentence
//postconditions: none
//return: nothing  
void printInfo(int numTimes, string sentence, string search, string replace)
{
   //print out the info about the new sentence 
   cout << "\nThe new string is \"" << sentence << "\"" << endl;
   cout << "and you replaced the word \"" << search << "\" with the word \"";
   cout << replace << "\" " << numTimes << " times." << endl;
}