Introduction  

This article explains how to add the capability of sending text (SMS) messages from a desktop applicaiton.  

Background    

The article focuses in an implementation using MFC / C++. While looking for a reliable and cheap solution for sending SMS messages programatically, I came across a company named CardBoardFish which covers 150 countries and provide an easy to use, yet powerful SDK for interfacing from any web site, mobile phone or desktop applicaiton, covering most platforms and development environments. Unfortunately, among the code sampels in their web site, there aren't any C++ samples, so I have decided to develop my own C++ implementation.

Sending SMS Messages Programatically

Most applicaitons and web sites used to send SMS messages as part of their scope or among other functionalities (i.e. sending alerts, etc.) use one of the following methods:
HTTP Web Service -  requires using HTTP "GET" method to send a given Web Service a command, using an API, which contains the credentials, parameters and the text for this message.
EMAIL 2 SMS  - uses the SMTP protocol to allow sending an email in a unique format, which encodes all required parameters (credentials, sender, reciever, etc.) as part of an Email. 
This article focuses on the first method, using a Web Service.

The API 

The following table lists all parameters that can (or should) be sent to the Web Service: 

Using the code    

The code in this article was developed under MFC / C++ using Visual Studio 2010 Ultimate.  I used Cheng Shi's HTTPClient (thanks Cheng!).   
In order to use the code for your own application, it is advised to read the specifications for an SDK namedHTTPSMS. Second, you need to open an account and to obtain your user name and password, which can be hardcoded in the source code, or entered during runtime.

The SendSMS Application      

SendSMS Screen
The main functionality of our application is obviously sending an SMS, which is done in the following function:
// SendSms  - by Michael Haephrati
BOOL SendSms(CString From, CString CountryCode, CString To,CString Message,CString *Status)
    // From - the ID or number you are sending from. This is what will appear at the recipient's cellphone. 
    // CountyCode - the code of the country you are sending the SMS to (for example: 44 is for the UK
    // To - is the number you are texting to, which should not contain any leading zeros, spaces, commas, etc.
    // Message - is the message you are sending, which can be any multi lingual text
    // The status returned would be either a confirmation number along with the text "OK", which means that the message
    // was delivered, or an error code. 
{
    BOOL result=FALSE;
    wstring user=L"PLACE_YOUR_USERNAME_HERE",pass=L"PLACE_YOUR_PASSWORD_HERE",request=L"";
    // 
    request=L"http://sms1.cardboardfish.com:9001/HTTPSMS?S=H&UN=";
    request+=user;    // user name
    request+=L"&P=";
    request+=pass;    // password
    request+=L"&DA="; 
    request+=(wstring)(CountryCode+To); // country code
    request+=L"&SA="; 
    request+=(wstring)From; // From (sender ID)
    request+=L"&M=";
    CString EncodedMessage; // Message
    
    CString ccc;
    EncodedMessage=ConvertHex(Message)+ConvertHex( L" here you can place your marketing piech, website, etc.");
    
    request+=(wstring)EncodedMessage; // Message to send

    request+=L"&DC=4";
    // Indicating that this message is encoded as opposed to plain text
Now we handle the HTTP "GET" request:
     WinHttpClient client(request); 
        
     client.SendHttpRequest(L"GET",true);
    // Get the response

    wstring httpResponseHeader = client.GetResponseHeader();
    wstring httpResponseContent = client.GetResponseContent();
    *Status=httpResponseContent.c_str();
    return result; 
}

Further Reading

Please refer to another article of mine, this time explaining how to do the same using iOS (IPhone / iPad).
 Michael Haephrati , CodeProject MVP 2013