ENERGY 211 / CME 211. Evolution

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1 ENERGY 211 / CME 211 Lecture 2 September 24, Evolution In the beginning, we all used assembly That was too tedious, so a very crude compiler for FORTRAN was built FORTRAN was still too painful to work with, so ALGOL 60 was created ALGOL 60 merged with COBOL to form CPL, for both science and business 2 1

2 Evolution, cont d CPL was too large and complex, so it was simplified to obtain BCPL BCPL was stripped down even more for systems programming, leading to B B was stripped down too much for more advanced operating systems, so it was enhanced to create C 3 From C to C++ Bjarne Stroustrup wanted a language that was efficient, like C, AND suitable for development of large applications, like SIMULA He enhanced C with SIMULA-like features to create C with classes Rick Mascitti first used the name C++ First commercial release in

3 Design Considerations There is no lower-level language between C++ and machine language (can write assembly in C++, but few do) For backward compatibility, any valid C program is a valid C++ program Unlike other languages, C++ supports multiple programming paradigms, such as procedural, object-oriented, generic, functional, etc. 5 From the Text you Type to the Program you Run As with other languages, you type your source code into source files, using the editor of your choice A C++ compiler translates the source code into object code, after checking for errors A linker combines your object code with other object code from existing libraries to create an executable file 6 3

Tools Needed for Projects Projects will be submitted electronically and graded on the elaine workstations Must have ssh client to connect Must be able to edit files in UNIX/Linux

4 Tools Needed for Projects Projects will be submitted electronically and graded on the elaine workstations Must have ssh client to connect Must be able to edit files in UNIX/Linux (with vi or emacs, for example), or transfer them using SecureFX Must be able to use GNU C++ compiler Visit computing.stanford.edu for needed software 7 Essential Software Link 8 4

5 Link to Download Page 9 Download SecureCRT 10 5

6 Launch SecureCRT 11 Create New Session 12 6

7 New Session Wizard 13 New Session Wizard, cont d 14 7

8 New Session Wizard, cont d 15 Connect to Elaine 16 8

9 Use SUNet Password 17 Connected! 18 9

10 Getting Started in Linux 19 Launching the vi editor 20 10

VERY Basic vi Usage Type i to enter insert mode Use ESC key to exit insert mode Commands (when not in insert mode): h: left, l: right, j: down, k: up x: delete character

11 VERY Basic vi Usage Type i to enter insert mode Use ESC key to exit insert mode Commands (when not in insert mode): h: left, l: right, j: down, k: up x: delete character at cursor Colon takes you to command prompt. There, use w to save, and q to exit Resource for learning vi: 21 Typing in your program 22 11

12 Saving 23 saved! 24 12

13 Exiting vi 25 Creating Executables in Linux The c++ command invokes the GNU C++ compiler on given source files, indicated by.cpp extension By default, it will also invoke the linker to create an executable Use c option to only create an object file which has.o extension By default, executable is called a.out Use o option to specify another name Can be run from the command prompt 26 13

14 Compiling and Executing 27 Dissecting hello.cpp // #include is a preprocessor directive that // specifies a header file to be included in the // program (in this case, iostream) #include <iostream> // When a program is run, its main function is // invoked. It returns an integer (int) value // indicating its status (not done here, though) int main() { // std::cout denotes the standard output // device, which is normally the screen. The // << operator, in this case, is used to // write data to this device. std::cout << "Hello world!" << std::endl; } 28 14

15 Delegating (or: Modularity!) hello.cpp: #include <iostream> (subroutine) void say_hello() // void means does not return a value { std::cout << "Hello world!" << std::endl; } hellomain.cpp: (main program) void say_hello(); // external functions must be declared int main() { say_hello(); // main passes the buck to say_hello } 29 Compiling Multiple Files Neither hello.cpp nor hellomain.cpp is a complete program, so we use c to compile only, and not link bramble06:~/demo211> c++ -c hello.cpp bramble06:~/demo211> c++ -c hellomain.cpp The previous commands created object (.o) files, which are now linked to create the executable program hello bramble06:~/demo211> c++ -o hello hello.o hellomain.o The ls command lists the current directory (like dir in Windows). The a.out is from before bramble06:~/demo211> ls a.out hello hello.cpp hello.o hellomain.cpp hellomain.o The. is used to denote the current directory, which, by default, is not in the search path used to locate programs bramble06:~/demo211>./hello Hello world! bramble06:~/demo211> 30 15

16 Managing Projects with make Managing projects with several source files can be tedious When you modify a source file, you need to recompile that file, and re-link The make command recompiles any out-of-date files automatically Useful for tasks such as cleaning up unnecessary files or changing compiler options 31 Creating Makefiles The make command uses a file called Makefile to determine how to proceed Makefile contains rules of the form target: prerequisites command where command builds target from the prerequisites Can define variables for convenience 32 16

17 Sample Makefile # All object files that must be linked into final executable OBJ= hello.o hellomain.o # Rule for building executable from object files # $@ is shorthand for the target of the rule hello: ${OBJ} c++ -o $@ ${OBJ} # Rule for compiling individual sources files into object files # $< is shorthand for the first prerequisite ${OBJ}: %.o: %.cpp c++ -c $< # Rule to clean up all output files clean: rm -f hello ${OBJ} 33 Using make With the Makefile, building executable is easy! bramble06:~/demo211> make c++ -c hello.cpp c++ -c hellomain.cpp c++ -o hello hello.o hellomain.o Reset hello.cpp s modified time to force recompile bramble06:~/demo211> touch hello.cpp Note that only hello.cpp is recompiled bramble06:~/demo211> make c++ -c hello.cpp c++ -o hello hello.o hellomain.o This removes all output files bramble06:~/demo211> make clean rm -f hello hello.o hellomain.o 34 17

18 Alternative Approaches Can edit source files on your computer, and transfer using SecureFX (available on Essential Software page), or Fetch if you re using a Mac Can do all of your work in Windows using MinGW Developer Studio In this case, should still compile and run final program on elaine before submitting 35 MinGW Developer Studio Abbreviated as MDS Available from MDS is an Integrated Development Environment (IDE), with editing, compiling and debugging performed inside the studio Uses gcc compiler 36 18

19 Launching MDS 37 Creating a New Project 38 19

20 MDS Project View 39 Adding a New Source File 40 20

21 Typing in Your Code 41 Building the Executable 42 21

22 The Build Process 43 Executing in MDS 44 22

23 Execution of Console App 45 What About Mac Users? Mac OS X is built on top of FreeBSD UNIX, so Linux discussion applies Can use ssh to connect to elaine OS X does not come with GNU compilers Can obtain freely from Apple Developer Connection by downloading xcode package (registration required) Visit

24 Next Time Learning some fundamentals of C++ Program Structure Simple Variables Literals Types Basic Exception Handling 47 24

Chapter 1 An Introduction to C++, Unix, SSH and Komodo Edit

Chapter 1 An Introduction to C++, Unix, SSH and Komodo Edit Contents 1 An Introduction to C++, Unix, SSH and Komodo Edit 1.1 Introduction 1.2 The C++ Language 1.2.1 A Brief Introduction 1.2.1.1 Recommended