Mind Boggling Error

[The Hobo]

This has me really stumped. This is a hangman program I wrote for my C++ class. I'm trying to have it store guessed letters in "char guesses[50]" yet somehow it's pulling other variables values into there and not working at all.

You might have to run the code to see what I mean:

#include <iostream>
#include <iomanip>
#include <stdlib.h>
#include <windows.h>
using namespace std;

//class for storing our words and definitions:
class word_list {
    public:
    char word[10];
    char hint[255];
};

//declare functions:
void wordinfo(int length, char word[10]);
void printxy(int x, int y, char text[255]);
void dopicture(int num);
int location(char string[10], char character);

int main() {
	
    int choice, chances = 0;
    word_list wordlist[5];
    char again;

    char word[10] = "";
    char guesses[50] = {""}; //********* <---
    char guess;
	
    //setup words (in uppercase) and hints:
    strcpy(wordlist[0].word,"DONKEY");
    strcpy(wordlist[0].hint,"This animal makes an ass of himself.");
    strcpy(wordlist[1].word,"PHONE");
    strcpy(wordlist[1].hint,"Ring! Ring!");
    strcpy(wordlist[2].word,"CHECKBOOK");
    strcpy(wordlist[2].hint,"It's easier to balance than a scale.");
    strcpy(wordlist[3].word,"BOAT");
    strcpy(wordlist[3].hint,"It floats. It carries. It");
    strcpy(wordlist[4].word,"KEYBOARD");
    strcpy(wordlist[4].hint,"Alphabetical/Numerical input device.");

    do {
        //setup our values:
        chances = 0;
        strcpy(word, "");
        //strcpy(guesses, ""); //********* <---
        choice = 0;

        system("CLS");
        //display welcome and menu:
        cout << "Welcome to Hangman, Man!" << endl << endl;
        cout << "Please choose a word (1) through (5): ";
        cin >> choice;

        //make sure acceptable value was entered:
        while (choice < 1 || choice > 5) {
            system("CLS");
            cout << "Bogus, man! Your choice needs to be a number (1) through (5)"
            << endl << endl;
            cout << "Please choose a word (1) through (5): ";
            cin >> choice;
        }
		

        //start the game:
        do {
            system("CLS");

            //Give our hints, etc:
            cout << "Hangman, man!" << endl << endl;
            cout << "Hint: " << wordlist[choice - 1].hint << endl;
            cout << "Word: ";
            wordinfo(strlen(wordlist[choice - 1].word), word);
			
            cout << endl;
            cout << "Guessed Letters: " << guesses << endl << endl; //********* <---
			
            //dopicture(chances);
						
            cout << "Enter guess: ";
            cin >> guess;
			
            //add letter to guessed letters (guesses)
            strcpy(guesses, strupr(guesses + guess)); //********* <---

            //check to see if letter exists in word
            if (location(wordlist[choice - 1].word, guess) != -1) {
                word[location(wordlist[choice - 1].word, guess)] = guess;
                if (strcmp(word, wordlist[choice - 1].word) == 0) {
                    system("CLS");
                    cout << "You won with " << 6 - chances << " chances!";
                    cout << endl << endl;
                    break;
                } else {
                    system("CLS");
                    cout << "Good Guess!" << endl << endl;
                    system("PAUSE");
                    system("CLS");
                }
            } else {
                chances++;
                if (chances == 6) {
                    //dopicture(chances);
                    cout << "Sorry, you didn't win this time..." << endl;
                    cout << "The word was " << wordlist[choice - 1].word << endl << endl;
                } else {
                    system("CLS");
                    cout << "Whoa! Not in this word, buddy. Try again!" << endl;
                    cout << "You have " << 6 - chances << " left." << endl << endl;
                    system("PAUSE");
                    system("CLS");
                }
            }
        } while (chances < 6);
		
        cout << "Would you like to play again? (y) or (n): ";
        cin >> again;
    } while (again == 'y');

    return 0;
}

int location(char string[10], char character) {
    for (int i = 0; i < strlen(string); i++) {
        if (string[i] == character) {
            return i;
            break;
        } 
    }

    return -1;
}

void wordinfo(int length, char word[10]) {
	
    for (int i = 0; i < length; i++) {
        if (word[i] == NULL) {
            cout << " _ ";
        } else {
            cout << " " << word[i] << " ";
        }
    }
}

Much thanks to anyone who can figure this out!