try to tidy up

src/libraries/Echo/echo.cpp

@@ -1,10 +1,8 @@
+#include "include/echo.h"
 #include <iostream>
-#include "echo.h"
 
 void echo(std::string echo_string) {
   std::cout << "The echo says " << echo_string << std::endl;
 }
 
-void echo2() {
-  echo("2");
-}
+void echo2() { echo("2"); }

src/programs/hello_c/main.c

@@ -1,5 +1,3 @@
 #include <stdio.h>
 
-int main(int argc, char** argv) {
-  printf("Hello World!\n");
-}
+int main(int argc, char **argv) { printf("Hello World!\n"); }

src/programs/hello_world/hello.cpp

@@ -1,8 +1,8 @@
-#include <iostream>
 #include <echo.h>
 
-#include "hello.h"
+#include "include/hello.h"
 
 void say_hello() {
+  // not found header
   echo("Hello World!");
 }

src/programs/hello_world/main.cpp

@@ -1,7 +1,9 @@
-#include "hello.h"
+#include "include/hello.h"
 // #include <echo.h>
-#include <string>
+// #include <string>
+
+int main(int argc, char **argv) {
+  // ahoi
 
-int main(int argc, char** argv) {
   say_hello();
 }

src/programs/say_hello/main.cpp

@@ -1,5 +1,6 @@
 #include <iostream>
 
-int main(int argc, char ** argv) {
+int main(int argc, char **argv) {
+  // just for info
   std::cerr << "Hello" << std::endl;
 }