diff --git a/evolution_by_versions/03_539kernel_progenitor/main.c b/evolution_by_versions/03_539kernel_progenitor/main.c
index a8f5fb1..8de7284 100644
--- a/evolution_by_versions/03_539kernel_progenitor/main.c
+++ b/evolution_by_versions/03_539kernel_progenitor/main.c
@@ -1,45 +1,46 @@
-volatile unsigned char *video = 0xB8000;
+volatile unsigned char *video = (unsigned char *)0xB8000;
 
 int nextTextPos = 0;
 int currLine = 0;
 
-void print( char * );
+void print(char *);
 void println();
-void printi( int );
+void printi(int);
 
 void kernel_main()
 {
-	print( "Welcome to 539kernel!" );
+	print("Welcome to 539kernel!");
 	println();
-	print( "We are now in Protected-mode" );
+	print("We are now in Protected-mode");
 	println();
-	printi( 539 );
+	printi(539);
 	println();
-	
-	while( 1 );
+
+	while (1)
+		;
 }
 
-void interrupt_handler( int interrupt_number )
+void interrupt_handler(int interrupt_number)
 {
 	println();
-	print( "Interrupt Received " );
-	printi( interrupt_number );
+	print("Interrupt Received ");
+	printi(interrupt_number);
 }
 
-void print( char *str )
+void print(char *str)
 {
 	int currCharLocationInVidMem, currColorLocationInVidMem;
-	
-	while ( *str != '\0' )
+
+	while (*str != '\0')
 	{
-        currCharLocationInVidMem = nextTextPos * 2;
+		currCharLocationInVidMem = nextTextPos * 2;
 		currColorLocationInVidMem = currCharLocationInVidMem + 1;
-		
-		video[ currCharLocationInVidMem ] = *str;
-		video[ currColorLocationInVidMem ] = 15;
-		
+
+		video[currCharLocationInVidMem] = *str;
+		video[currColorLocationInVidMem] = 15;
+
 		nextTextPos++;
-		
+
 		str++;
 	}
 }
@@ -49,21 +50,21 @@ void println()
 	nextTextPos = ++currLine * 80;
 }
 
-void printi( int number )
+void printi(int number)
 {
-	char* digitToStr[] = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
-	
-	if ( number >= 0 && number <= 9 )
+	char *digitToStr[] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
+
+	if (number >= 0 && number <= 9)
 	{
-		print( digitToStr[ number ] );
+		print(digitToStr[number]);
 		return;
 	}
 	else
 	{
 		int remaining = number % 10;
 		number = number / 10;
-		
-		printi( number );
-		printi( remaining );
+
+		printi(number);
+		printi(remaining);
 	}
 }