Merge branch 'main' into patch-5

Author: ohkimur

chapter_4/exercise_4_04/stack.c

@@ -215,10 +215,6 @@ int getop(char s[])
       s[++i] = c = next;
     }
   }
-  else
-  {
-    c = getch();
-  }
 
   if (isdigit(c))
   {

chapter_4/exercise_4_06/variables.c

@@ -304,3 +304,7 @@ int getop(char s[])
 
   return NUMBER;
 }
+/* To prevent the variable checking in getop() from overlapping with the letter commands,
+make sure you set the commands to capital letters and explicitly tell the getop() to only
+check for variable-getting if the character is not capital
+e.g insteat of "if (isalpha(c))" you add "if (isalpha(c) && !(c >= 'A' && c >= 'Z'))"*/

chapter_4/exercise_4_13/reverse.c

@@ -27,6 +27,13 @@ void reverse(char str[])
 
     str[j++] = c;
   }
+
+  // if whole reverse process is complete, reset the static variables to make this function reusable
+  if (str[j] == '\0')
+  {
+    i = 0;
+    j = 0;
+  }
 }
 
 // NOTE: As a simple observation when recursive functions are used, static