C language - operation replaces mutiple array elements instead of one - c

Question

I am in the process of creating hangman in C language, but there is one problem that I cannot quite grasp. When a user correctly guesses one of the letters that the word that is being guessed has, the program replaces all of previously guessed letters to the one user just put. What is the source of this problem?
#include<stdio.h>
#include <stdlib.h>
int main()
{
srand(time(NULL));
int x = 0, isCompleted, matchFound, numberOfTries = 7;
char letterGuess[1];
int randomIndex = rand()%14;
const char *wordArray[14];
const char *guessedWord[10];
const char *usedLetters[17];
for (int k = 0; k < 10; k++) {
guessedWord[k] = "_";
}
wordArray[0] = "butonierka";
wordArray[1] = "centyfolia";
wordArray[2] = "chiroplast";
wordArray[3] = "cmentarzyk";
wordArray[4] = "chrustniak";
wordArray[5] = "budowniczy";
wordArray[6] = "cholewkarz";
wordArray[7] = "cornflakes";
wordArray[8] = "brzydactwo";
wordArray[9] = "germanofil";
wordArray[10] = "lichtarzyk";
wordArray[11] = "lutowniczy";
wordArray[12] = "mikrocysta";
wordArray[13] = "tryskawiec";
const char *wordToGuess = wordArray[randomIndex];
for(int i = 0; i < 10; i++) {
printf(" %s ", guessedWord[i]);
}
printf("\n");
while(numberOfTries != 0 && isCompleted != 10) {
matchFound = 0;
isCompleted = 0;
printf("Please give a lowercase letter\n");
printf("Left tries: %d\n", numberOfTries);
scanf("%s", &letterGuess);
for (int z = 0; z < 17; z++) {
if (usedLetters[z] == letterGuess[0]) {
matchFound = 1;
}
}
if (letterGuess[0] >= 'a' && letterGuess[0] <= 'z' && matchFound == 0) {
usedLetters[x] = letterGuess[0];
x++;
for (int j = 0; j < 10; j++) {
if (letterGuess[0] == wordArray[randomIndex][j])
guessedWord[j] = letterGuess;
matchFound = 1;
}
}
if (matchFound == 0) {
numberOfTries--;
}
for(int z = 0; z < 10; z++) {
printf(" %s ", guessedWord[z]);
}
printf("\n");
} else {
if (matchFound == 1) {
printf("You've already given such letter!!\n");
} else {
printf("Wrong input, please try again!\n");
}
}
for (int k = 0; k < 10; k++) {
if (guessedWord[k] != "_") {
isCompleted++;
}
}
if (isCompleted == 10) {
printf("You have correctly guessed a word! Congrats!!\n");
}
printf("\n\n");
}
printf("The word was: %s\n", wordArray[randomIndex]);
printf("Game over!!\n");
}

Answer 1

The problem is that you're storing letterGuess, rather than individual characters. So each time letterGuess is updated with a new guess, all references to it change. Also, letterGuess is too short, leaving no room for the terminating null character.
The best solution is to make letterGuess a char (or an int), not an array, and to make guessedWord a char [] rather than a char *[]. There is no reason to use strings for single characters. That will solve the string-sharing problem.