Added feature foo to the project

foo.c

@@ -0,0 +1,7 @@
+#include <stdio.h>
+#include "foo.h"
+
+
+void foo(void) {
+	puts("Hello World from foo()");
+}

foo.h

@@ -0,0 +1,6 @@
+#ifndef FOO_H
+#define FOO_H
+
+void foo(void);
+
+#endif

main.c

@@ -1,8 +1,12 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include "foo.h"
+
 int main(void) {
 	puts("Hello World");
 
+	foo();
+
 	return EXIT_SUCCESS;
 }