diff --git a/src/main/c/hangman.c b/src/main/c/hangman.c
index 847a301..4a8045d 100644
--- a/src/main/c/hangman.c
+++ b/src/main/c/hangman.c
@@ -15,6 +15,7 @@ void nameAusgeben();
 void levelauswahl();
 void hauptSpiel(int level);
 void draw_hangman(int attempts);
+void add_guessed_letter(char* guessed_letters, char guessed_letter);
 
 void protokoll(){
 	clear_screen();
@@ -249,4 +250,12 @@ void draw_hangman(int attempts) {
         default:
             break;
     }
+}
+
+void add_guessed_letter(char* guessed_letters, char guessed_letter){
+	for (int i = 0; i < strlen(guessed_letters); i++){
+		if (guessed_letters[i] == guessed_letter){
+			return;
+		}
+	}
 }
\ No newline at end of file