HELP - New to C++ and most other programming

The program I wrote below is supposed to play a guessing game based on the computer picking a random letter. All it does is loop twice then say you win. Also the if higher/lower portion is not processing properly. eg: (depending on if the if statement is guess < randomLetter) guess a - the letter is lower, guess a - You win. I have spent hours looking thru this site and others for help for most of my problems but I generally can't find the answer I need or am just so C++ disabled I can't see the answer in front of me.

#include <iostream>
#include <string>
#include <algorithm>
#include <cstdlib>
#include <ctime>
using namespace std;

int main()
{
//declaration of variables
int number = 0;
string letters = "abcdefghijklmnopqrstuvwxyz";
string randomLetter = "";
string guess = "";

//initialize the random number generator
srand(time(NULL));

//assign a the random value to number
number = 0 + rand() % (26 - 10 + 1);

//find the letter that coresponds to the number
randomLetter.assign(letters, number, 0);

//get users guess
cout << "The computer has secretly picked a letter." << endl;
cout << "Try to guess the letter." << endl;
cout << "Your guess is: ";
getline(cin, guess);
transform(guess.begin(), guess.end(), guess.begin(), tolower);

// verify that user entered only one letter
if (guess.size() == 1)
{

//repeat code till users guess is correct
while (guess != randomLetter)
{
//display higher or lower clue
if (guess < randomLetter)
cout << "The letter you are looking for is lower in the alphabet." << endl;
else
cout << "The letter you are looking for is higher in the alphabet." << endl;
//end ifs

cout << "Please try again!" << endl;
cout << "Your guess is: ";
getline(cin, guess);
transform(guess.begin(), guess.end(), guess.begin(), tolower);
}//end while

cout << "That is correct!" << endl;
cout << " YOU WIN !!! " << endl;

}
else
cout << "Please enter one letter only.";

return 0;
}// end of main function

You've got the condtional operator the wrong way round. If guess is less than randomLetter then the letter you're looking for will be higher in the alphabet. Also I think you're making the task more compilcated by using strings when you're only guessing single characters -

Code:

---

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

int main()
{
        //declaration of variables
        char randomLetter = 0;
        char guess = 0;

        //initialize the random number generator
        srand(time(NULL));

        //assign a the random value to number
        randomLetter ='a'+ rand() % 26;


        //get users guess
        cout << "The computer has secretly picked a letter." << endl;
        cout << "Try to guess the letter." << endl;
        cout << "Your guess is: ";
        cin >> guess;

        guess = tolower(guess);

        //repeat code till users guess is correct
        while (guess != randomLetter)
        {
        //display higher or lower clue
                if (guess > randomLetter)
                        cout << "The letter you are looking for is lower in the alphabet." << endl;
                else
                        cout << "The letter you are looking for is higher in the alphabet." << endl;
        //end ifs

                cout << "Please try again!" << endl;
                cout << "Your guess is: ";
                cin>> guess;
                guess = tolower(guess);
        }//end while

        cout << "That is correct!" << endl;
        cout << " YOU WIN !!! " << endl;

        return 0;
}// end of main function

---

Sorry I should have been more explicit. This a homework assign. and I must be able to except more that 1 char. from the user and display the warning. As for the operator it doesn't matter which way it is < or > except for the cout statement the program does not run properly which means I have messed up the logic and I am not sure how. Thanks for the answer you gave though it will help me get my head around this language.