CppCMS URL Dispatching and Mapping fails. Incomplete code?

From http://cppcms.com/wikipp/en/page/cppcms_1x_tut_url_mapping

After rewriting, hello.cpp code is below:

#include <cppcms/application.h>
#include <cppcms/service.h>
#include <cppcms/http_response.h>
#include <cppcms/url_dispatcher.h>
#include <cppcms/url_mapper.h>
#include <cppcms/applications_pool.h>
#include <iostream>
#include <stdlib.h>

hello(cppcms::service &srv) :
    cppcms::application(srv)
{
    dispatcher().assign("/number/(\\d+)",&hello::number,this,1);
    mapper().assign("number","/number/{1}");

    dispatcher().assign("/smile",&hello::smile,this);
    mapper().assign("smile","/smile");

    dispatcher().assign("",&hello::welcome,this);
    mapper().assign("");

    mapper().root("/hello");
}


void number(std::string num)
{
    int no = atoi(num.c_str());
    response().out() << "The number is " << no << "<br/>\n";
    response().out() << "<a href='" << url("/") << "'>Go back</a>";
}

void smile()
{
    response().out() << ":-) <br/>\n";
    response().out() << "<a href='" << url("/") << "'>Go back</a>";
}

void welcome()
{
    response().out() <<
        "<h1> Wellcome To Page with links </h1>\n"
        "<a href='" << url("/number",1)  << "'>1</a><br>\n"
        "<a href='" << url("/number",15) << "'>15</a><br>\n"
        "<a href='" << url("/smile") << "' >:-)</a><br>\n";
}

But now, it throw an error on compiling:

hello.cpp:10:27: error: ISO C++ forbids declaration of ‘hello’ with no type [-fpermissive]
hello.cpp: In function ‘int hello(cppcms::service&)’:
hello.cpp:11:5: error: only constructors take member initializers
hello.cpp:13:16: error: ‘dispatcher’ was not declared in this scope
hello.cpp:13:43: error: ‘hello’ is not a class or namespace
hello.cpp:13:57: error: invalid use of ‘this’ in non-member function
hello.cpp:14:12: error: ‘mapper’ was not declared in this scope
hello.cpp:16:35: error: ‘hello’ is not a class or namespace
hello.cpp:16:48: error: invalid use of ‘this’ in non-member function
hello.cpp:19:29: error: ‘hello’ is not a class or namespace
hello.cpp:19:44: error: invalid use of ‘this’ in non-member function
hello.cpp: In function ‘void number(std::string)’:
hello.cpp:29:14: error: ‘response’ was not declared in this scope
hello.cpp:29:14: note: suggested alternative:
/usr/local/include/cppcms/http_response.h:31:19: note:   ‘cppcms::http::response’
hello.cpp:30:47: error: ‘url’ was not declared in this scope
hello.cpp: In function ‘void smile()’:
hello.cpp:35:14: error: ‘response’ was not declared in this scope
hello.cpp:35:14: note: suggested alternative:
/usr/local/include/cppcms/http_response.h:31:19: note:   ‘cppcms::http::response’
hello.cpp:36:47: error: ‘url’ was not declared in this scope
hello.cpp: In function ‘void welcome()’:
hello.cpp:41:14: error: ‘response’ was not declared in this scope
hello.cpp:41:14: note: suggested alternative:
/usr/local/include/cppcms/http_response.h:31:19: note:   ‘cppcms::http::response’
hello.cpp:43:39: error: ‘url’ was not declared in this scope

I think the new hello.cpp codes is incomplete (and no idea the complete code), but because it said "rewrite", I just removed the old code and create new one.

I've tried combine with old Hello World but no luck.

In the linked-to example the constructor is defined inside the class (in the header). If you define it in a .cpp file, you will have to add the class name to the constructor and member functions.

hello::hello(cppcms::service &srv) :
    cppcms::application(srv)
{

...

void hello::number(std::string num)
{

Otherwise the compiler believes that you are adding some unrelated free functions.