University:
Boston University
Course:
MET CS 201 | Introduction to Programming
Academic year:

2022
Views:

273

Pages:

20
Author:

Jarrett Richard

NetBeans http://www.netbeans.org  In this tutorial we will use the NetBeans integrated development environment (IDE) for writing and compiling C++  Run it right on the terminal or on the SCC (module load netbeans/8.2.0)  About NetBeans  Originally developed at the Charles University in Prague, then by Sun Microsystems, then by Oracle, now part of the Apache Software Foundation.  cross-platform: supported on Mac OSX, Linux, and Windows  Oriented towards Java but also supports C and C++.  Short learning curve compared with other IDEs such as Eclipse or Visual Studio  Generates its own Makefiles and builds with make, standard tools for building software. IDE Advantages        Handles build process for you Syntax highlighting and live error detection Code completion (fills in as you type) Creation of files via templates Built-in debugging Code refactoring (ex. Change a variable name everywhere in your code) Higher productivity than plain text editors!      IDEs available on the SCC NetBeans(used here) geany – a minimalist IDE, simple to use Eclipse – a highly configurable, adaptable IDE. Very powerful but with a long learning curve Spyder – Python only, part of Anaconda Emacs – The one and only. Some Others  Xcode for Mac OSX  Visual Studio for Windows  Code::Blocks (cross platform) Opening NetBeans  Open NetBeans  click icon on OSX or Windows  Type netbeans on the SCC or Linux  Create a new project under the File Menu or by clicking on the icon  Choose the C/C++ category and C/C++ Application  Click the Next button.  Give the project the name Test.  Under Tool Collection choose Clang or Gnu (depending on what is shown)  Click Finish  Check that everything works.  Click the green triangle to compile & run the program.  Windows will probably ask to have some tools specified.  Set the base directory for Clang to:  C:\Program Files\LLVM\bin  Debugger to:  C:\Program Files\LLVM\bin\lldb.exe  The make program is found in:  C:\Program Files (x86)\GnuWin32\bin Enable C++11 standard  Click the C++ Compiler category and choose C++11 option under the C++ Standard menu.  Right-click on your project name and choose Properties Make the program do something….  Edit the main.cpp program in your Test project to look like the code to the right.  This is text – it can be copied and pasted from the presentation…but it’s better to type it.  When done, click the green triangle again to run the updated program. #include using namespace std; int main(int argc, char** argv) { cout << "Hello World!" << endl ; return 0; } Hello, World!  Build messages  Run output Behind the Scenes: The Compilation Process Hello, World! explained The main routine – the start of every C++ program! It returns an integer value to the operating system and (in this case) takes arguments to allow access to command line arguments. The return statement returns an integer value to the operating system after completion. 0 means “no error”. C++ programs must return an integer value.  loads a header file containing function and class definitions   Loads a namespace called std. Namespaces are used to separate sections of code for programmer convenience. To save typing we’ll always use this line in this tutorial. Hello, World! explained      cout is the object that writes to the stdout device, i.e. the console window. It is part of the C++ standard library. Without the “using namespace std;” line this would have been called as std::cout. It is defined in the iostream header file. << is the C++ insertion operator. It is used to pass characters from the right to the object on the left. endl is the C++ newline character. Header Files  C++ (along with C) uses header files as to hold definitions for the compiler to use while compiling.  A source file (file.cpp) contains the code that is compiled into an object file (file.o).  The header (file.h) is used to tell the compiler what to expect when it assembles the program in the linking stage from the object files.  Source files and header files can refer to any number of other header files.  When compiling the linker connects all of the object (.o) files together into the executable. Make some changes  Let’s put the message into some variables of type string and print some numbers.  Things to note:  Strings can be concatenated with a + operator.  No messing with null terminators or strcat() as in C  Some string notes:  Access a string character by brackets or function:  msg[0]  “H” or msg.at(0)  “H”  C++ strings are mutable – they can be changed in place.  Re-run and check out the output. #include using namespace std; int main() { string hello = "Hello"; string world = "world!"; string msg = hello + " " + world ; cout << msg << endl; msg[0] = 'h'; cout << msg << endl; return 0; } A first C++ class: string  string is not a basic type (more on those later), it is a class.  string hello creates an instance of a string called “hello”.  hello is an object.  Remember that a class defines some data and a set of functions (methods) that operate on that data.  Let’s use NetBeans to see what some of these methods are…. #include using namespace std; int main() { string hello = "Hello"; string world = "world!"; string msg = hello + " " + world ; cout << msg << endl; msg[0] = 'h'; cout << msg << endl; return 0; } A first C++ class: string  Update the code as you see here.  After the last character is entered NetBeans will display a large number of methods defined for the msg object.  If you click or type something else just delete and re-type the last character.  Ctrl-space will force the list to appear. #include using namespace std; int main() { string hello = "Hello"; string world = "world!"; string msg = hello + " " + world ; cout << msg << endl; msg[0] = 'h'; cout << msg << endl; msg. return 0; } A first C++ class: string A first C++ class: string     Start typing “msg.size()” until it appears in the list. Once it’s highlighted (or you scroll to it) press the Tab key to auto-enter it. An explanation appears below. “Returns the number of characters in a string not including any null-termination.” #include A first C++ class: string  Tweak the code to print the number of characters in the string, build, and run it.  size() is a public method, usable by code that creates the object.  The internal tracking of the size and the storage itself is private, visible only inside the string class source code. using namespace std; int main() { string hello = "Hello" ; string world = "world!" ; string msg = hello + " " + world ; cout << msg << endl ; msg[0] = 'h'; cout << msg << endl ; cout << msg.size() << endl ; return 0; }  Note: while the string class has a huge number of methods your typical C++ class has far fewer!  cout prints integers without any modification!