Fixed bugs in get_history_size and load_history functions.

shell.c

@@ -174,7 +174,7 @@ int get_cmnd_from_history(long commandNum) {
 
 int get_history_size() {
     int historySize = 0;
-    while (history[historySize].line != NULL) {
+    while (history[historySize].line != NULL && historySize < MAX_HISTORY_LENGTH) {
         historySize++;
     }
 
@@ -315,7 +315,7 @@ void load_history() {
     if (fp != NULL) {
         String line = malloc(sizeof(char) * MAX_INPUT_LENGTH);
         int index = 0;
-        while (fgets(line, MAX_INPUT_LENGTH, fp) != NULL && index <= MAX_HISTORY_LENGTH) {
+        while (fgets(line, MAX_INPUT_LENGTH, fp) != NULL && index < MAX_HISTORY_LENGTH) {
             // Remove trailing newlie character
             char *pos = strchr(line, '\n');
             if (pos != NULL) {