New curses (ncurses) is an openly distributable library of functions that deals with an application's user interface (UI) in text mode. It creates a wrapper over terminal abilities. ncurses is a free software, it is not an open source. It provides functions to make imaginary screen windows for logical calculations, print windows, and so on. Libraries for panels, menus, and forms use the ncurses library and extend the basic functionality of ncurses as required. We can make applications that contain numerous windows, menus, panels, and forms; windows can be overseen autonomously, can give scrollability, and can even be covered up.

Menus give the client a simple order determination choice, forms permit the formation of easy−to−use information sections and show windows, and panels stretch out the abilities of ncurses to manage covering and...

Code reusability is one of the key principles in programming. For example, in an application we may use a certain functionality multiple times, so we keep it in a useful place and refer it from that place, whenever we need it in our application. Now, suppose our application implemented some common functionality which we can use in other applications, in this case, instead of writing the same logic again, we can create a library. It is easily distributable and reusable.

Asp.NET Core supports cross-platform programming, so any Linux user who has built many reusable libraries, API-like console support, and filesystem access, and wants to use them while writing code in ASP.NET Core, can access them. In this section, we will see how to access these native libraries (.dll) and Mono libraries (.so) in the program.

Common Language Infrastructure...

In the previous section, we learned about cross-platform implementation, and how to Interop with existing native and Mono libraries. To demonstrate interoperability, we created small sample applications. Let's start with building our first native library in C++. Follow these steps:

1. Open Visual Studio and select Windows Desktop under Visual C++ and select the project type Dynamic-Link Library (DLL). In this example, we name the project ExampleDLL and provide the location where we want to create the project:

2. Right-click on the header files folder and create a new header file. In this example, we named it Calculate.h. The Calculate header file contains mathematical operations such as the summation of two integer numbers, multiplication, and division:

#ifndef Calculate
#define Calculate
 
extern "C"
{
  __declspec(dllexport...

Now that we know the fundamentals, let's start building a sample application which implements ncurses. We will create a C# application which imports a C library or we can say .so file. This library has implemented ncurses functions. P/Invoke allows us to use those ncurses functions in our C# application.

First, we will create a C program which implements ncurses functions using an ncurses header. Let's create an application which takes an input character; this character will be printed in a window, based on the number of rows and columns the user enters from the application where we will import this library. The function drawCharOnWindow() prints the character, based on the number of rows and columns present in the window; it takes character, row, and column as input parameters. We get the size of the window...

In this chapter, we learned about the ncurses library and how to use this library in C or C++ programs. Also, we learned about how to reuse libraries created in Ubuntu or on a Linux machine which implemented ncurses in a .NET Core 2.0 application, using P/Invoke. We have seen how Mono works efficiently with a Linux machine and makes programming easy in .NET Core 2.0, using C# for Linux user. The next chapter will be very interesting, and it will be where we will build our first game, Tic-Tac-Toe, using .NET Core and we will learn about its compilation, building, and testing.