Optionally memset the malloced memory

hogs/malloc.c

@@ -1,10 +1,17 @@
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
+#include <unistd.h>
 
 int main(int argc, char **argv) {
     size_t size = strtoul(argv[1], NULL, 0);
     char *p = malloc(size);
     printf("%zu bytes at %p\n", size, p);
+    if (argv[2]) {
+        unsigned char c = strtoul(argv[2], NULL, 0);
+        memset(p, c, size);
+        printf("filled with %zu %02x bytes\n", size, c);
+    }
     sleep(10);
     return 0;
 }