feat(input): implement file parsing for word list

Startcode/input.c

@@ -2,11 +2,49 @@
 #include <string.h>
 #include <ctype.h>
 
-// TODO:
-// eine Funktion implementieren, die ein einzelnes Wort aus einer Textdatei (words.txt) einliest und als C-String zurückgibt.
+/*
+Read a single word from file and store it in buffer.
+Returns the length of the word, or 0 if no more words are available (EOF).
+*/
+static int readSingleWord(FILE *file, char buffer[MAX_WORD_LEN])
+{
+    int len = 0;
+    int c;
+
+    //clear leading seperators
+    while((c = fgetc(file)) != EOF && (c == ',' || c == ';' || c == ' ' || c == '\n')) {}
+
+    //check for empty file
+    if(c == EOF)
+        return 0;
+
+
+    //read word
+    do
+    {
+        if(len < MAX_WORD_LEN - 1) // -1 to leave space for '\0'
+        {
+            buffer[len] = toupper((unsigned char)c);
+            len++;
+        }
+        c = fgetc(file);
+    }
+    while(c != EOF && !(c == ',' || c == ';' || c == ' ' || c == '\n'));
+
+    //append string end-delimiter
+    buffer[len] = '\0';   // '\0' marks the end of a string, we need to apend it for strcpy
+    return len;
+}
 
 // Read words from file and store in 'words' array
 int readWords(FILE *file, char words[][MAX_WORD_LEN], unsigned int maxWordCount)
 {
+    char buffer[MAX_WORD_LEN];
+    unsigned int wordCount = 0;
+    int len;
 
+    while(wordCount < maxWordCount && (len = readSingleWord(file, buffer)) > 0)
+        strcpy(words[wordCount++], buffer);
+
+    return wordCount;
 }