diff --git a/level04/source.c b/level04/source.c
index 06e286d..c27b7f1 100644
--- a/level04/source.c
+++ b/level04/source.c
@@ -7,31 +7,23 @@
 
 int main(void)
 {
-	int stat_loc;
 	char s[128];
-	int v6;
-	int v7;
-	int v8;
-	pid_t v9;
+	int wstatus;
+	pid_t pid;
 
-	v9 = fork();
+	pid = fork();
 	memset(s, 0, sizeof(s));
-	v8 = 0;
-	stat_loc = 0;
-	if (v9) {
+	if (pid) {
 		do {
-			wait(&stat_loc);
-			v6 = stat_loc;
-			if ((stat_loc & 0x7F) == 0 ||
-			    (v7 = stat_loc,
-			     (char)((stat_loc & 0x7F) + 1) >> 1 > 0)) {
+			wait(&wstatus);
+			if (WIFSIGNALED(wstatus) ||
+			    ((char)(WIFSIGNALED(wstatus) + 1) >> 1 > 0)) {
 				puts("child is exiting...");
 				return 0;
 			}
-			v8 = ptrace(PTRACE_PEEKUSER, v9, 44, 0);
-		} while (v8 != 11);
+		} while (ptrace(PTRACE_PEEKUSER, pid, 44, 0) != 11);
 		puts("no exec() for you");
-		kill(v9, 9);
+		kill(pid, 9);
 	} else {
 		prctl(1, 1);
 		ptrace(PTRACE_TRACEME, 0, 0, 0);