using namespace std;

bool IsPalindrome(string);

main()
{
	string userInput;
	int i,j,k;

	cout<< "Type in your word or sentence: ";
	cin >>userInput;

	if(IsPalindrome(userInput) == true)
		cout << "\nThe string is a palindrome.";

	else
		{
		cout << "\nThe string is not a palindrome:";
		cout << " the character in position ";
		cout << j <<" is "<< "'"<< userInput[j] << "', while the";
		cout << " character in position ";
		cout <<	k <<" is "<< "'"<< userInput[k] <<"'.";
		}
	return 0;
}

bool IsPalindrome(string userInput)
{
	int i,j=0,k=0,N=userInput.length();

	bool isPal = true;

	for (i=0;i<N;++i)
	{
		if (userInput[i]!= userInput[N-1-i])
		{
			userInput[i]=j;  
			userInput[N-1-i]=k;
			isPal = false;
		}
	}
    return isPal;
}

bool IsPalindrome(string userInput)
{
    int i,j=0,k=0,N=userInput.length();
    bool isPal = true;
    for (i=0;i<N;++i)
    {
        if (userInput[i]!= userInput[N-1-i])
        {
            userInput[i]=j;    // why are you replacing the character with a 0?
            userInput[N-1-i]=k;// why are you replacing the character with a 0?
            isPal = false;
        }
    }
    return isPal;
}

bool IsPalindrome(string userInput)

bool IsPalindrome(string userInput,char &left,char &right,
                                                 int &left_pos,int &right_pos)
//pass all the characters by reference
//if the string is not a pallindrome you display all the 'extra' parameters.

{
	int i,N=userInput.length();

	bool isPal = true;

	for (i=0;i<N;++i)
	{
		if (userInput[i]!= userInput[N-1-i])
		{
			left = userInput[i];  
			right = userInput[N-1-i];
			left_pos =i;
			right_pos = N-1-i;
            isPal = false;
		    break; //You now know the string is not a pallindrome,
            //and you were supposed to find out the FIRST
           //  non matching characters.why to continue further?
        }
	}
    return isPal;
}

.
.
.
.
{
		cout << "\nThe string is not a palindrome:";
		cout << " the character in position ";
		cout << left_pos <<" is "<< "'"<< left << "', while the";
		cout << " character in position ";
		cout <<	right_pos <<" is "<< "'"<< right <<"'.";
		}

#include <iostream>
#include <string>

using namespace std;

bool IsPalindrome(string, int*, int*); // two additional arguments.

int main()  // explicitly specify return type.
{
	string userInput;
	int j=0,k=0;  // elminate i.

	cout<< "Type in your word or sentence: ";
//	cin >> userInput; // this will only get a word, not a string.
	getline(cin,userInput); // this will get both.

	cout << "\nThe string \"" << userInput << "\" is "; // common to both conditions
	
	if(IsPalindrome(userInput, &j, &k) == true) // now pass j,k for potential assignment
		cout << "a palindrome.";

	else
	{
		// if we get here, then j and k will have the indexes.
		cout << "not a palindrome:" << endl;
		cout << "The character in position ";
		cout << j <<" is "<< "'"<< userInput[j] << "', while the";
		cout << " character in position ";
		cout <<	k <<" is "<< "'"<< userInput[k] <<"'.";
	}

	return 0;
}

bool IsPalindrome(string userInput, int* j, int* k)
{
	int i, N=userInput.length(); // eliminate j,k.
	int oppositeEnd = 0; // new variable.

	bool isPal = true;

	// Add 'isPal to loop's condition. No need to check
	// the rest of the string once a mismatch is found.
	for (i=0;i<N && isPal;++i)
	{
		oppositeEnd = N-1-i; // calculate N-1-i ONCE.
		
		if (userInput[i] != userInput[oppositeEnd])
		{
			*j = i;		// store the left mismatch index.
			*k = oppositeEnd; // store the right mismatch index.
			isPal = false;
		}
	}
    
	return isPal;
}

#include<iostream.h>
#include<conio.h>
#include<string.h>

void main()
{
  clrscr();
   char str[20];  int i,c=0;
  cout<<"enter string";
   gets(str);

    for(i=0;i<strlen(str);i++)
    {
       if(a[i]==a[strlen(str)-i)
        c++;
       else
       cout<<" character at position"<<i+1<<" is" <<a[i]<<" while at position"<<strlen(str)-i+1<<" is "<< a[strlen(str)-i+1];
}

if(c==strlen(str)/2)
 cout<<"its a pallindrome string";

getch();
}

// #include<iostream.h>
// Standard C++ library header files don't have extensions
#include <iostream>
// I'll just remove this, since I think clearing the screen
// in this case is pretty trivial
// Not worth teaching non-standardness to those new to C++
// #include<conio.h>
// #include<string.h>
#include <string>

// void main()
// main() must return an int
int main()
{
    // These identifiers are wrapped inside the std namespace
    // A using declaration is a simple way to make available the
    // names you need unless you want to use fully qualified
    // names at every occasion
    using std::string;
    using std::cout;
    using std::getline;
    //  clrscr();
    //   char str[20];  int i,c=0;
    // A "C++" way could be to use std::string
    string str;
    int i, c = 0;
    
    cout << "enter string" << std::endl;
    //   gets(str);
    // Replace with std::getline()
    getline(std::cin, str);

    // Use string::size() to find size of string
    for (i = 0; i < str.size() ; i++)
    {
        // What's the 'a' here? Hasn't been declared
        // I'm assuming 'a' == 'str'
        // if(a[i]==a[strlen(str)-i)
        if (str[i] == str[str.size() - i - 1])
            c++;
        else
        {
            cout << " character at position " << i + 1 << " is " << str[i]
                 // the + 1 here should be - 1?
                 // << " while   at position " << str.size() - i + 1 << " is "
                 // << str[str.size() - i + 1] << std::endl;
                 << " while   at position " << str.size() - i - 1 << " is "
                 << str[str.size() - i - 1] << std::endl;
        }
    }

    // Did you consider what is the value of c when the string is a palindrome?
    // Is it str.size() / 2 or is it really str.size() ?
    // if (c == str.size() / 2)
    if (c == str.size())
        cout << "its a palindrome string";

    // getch();
    
    return 0;
}