hello.c included in main.c and compiled successfully

c-basic/main.c

@@ -1,16 +1,10 @@
 #include <stdio.h>
-
-#ifndef HEX_READ_SCANF_H
-#define HEX_READ_SCANF_H
-
-extern void hex_scan();
-
-#endif // HEX_READ_SCANF_H
+#include "hello.c"
 
 int main()
 {
 
-  hex_scan();
-
+  hello();
+  
   return 0;
 }