handle upper case letters

src/main/c/Hangman/playHangman.c

@@ -1,5 +1,14 @@
 #include "playHangman.h"
 
+// Converts the letter to lower case
+char toLower(char ch) {
+    // Convert uppercase letter to lowercase manually
+    if (ch >= 'A' && ch <= 'Z') {
+        return ch + ('a' - 'A');
+    }
+    return ch;
+}
+
 
 void playHangman(char *wordToGuess) {
     int mistakes = 0;
@@ -19,11 +28,14 @@ void playHangman(char *wordToGuess) {
         scanf(" %c", &guess);
 
         // Check if the guess is lower case and is a letter (valid)
-        if (!isalpha(guess) || isupper(guess)) {
-            printf("Please enter a valid lowercase alphabet.\n");
+        if (!isalpha(guess)) {
+            printf("Please enter a valid alphabet.\n");
             continue;
         }
 
+        // Convert uppercase letter to lowercase
+        guess = toLower(guess);
+
         // Check if the guess is a single letter
         if (strlen(&guess) != 1) {
             printf("Please enter only one letter.\n");