computer engineering 1 nd semester

Computer Engineering 1nd Semester

Dr. Rabie A. Ramadan

http://rabieramadan.org

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Basics of C++ Environment

Phases of C++ Programs • Edit

• Preprocess

• Compile

• Link

• Load

• Execute

Loader

PrimaryMemory

Program is created inthe editor and storedon disk.

Preprocessor programprocesses the code.

Loader puts programin memory.

CPU takes eachinstruction andexecutes it, possiblystoring new datavalues as the programexecutes.

CompilerCompiler createsobject code and storesit on disk.

Linker links the objectcode with the libraries,creates a.out andstores it on disk

Editor

Preprocessor

Linker

 CPU

PrimaryMemory

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Disk

Disk

Disk

Disk

Disk

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Programming environment

MSVC (windows) GCC (Linux, Unix) --------------------------------- Many other compilers are available: Ex.

• Borland c++

• Eclips

What is IDE

• integrated development environment : is a software application that provides comprehensive facilities to computer programmers for software development

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Using MSVC

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Linux & Unix

gcc command , and g ++ is the C++ compiler, while cc and CC are the Sun C and C++ It works on both Linux & Unix GCC step by step

• 1. Write your program on one of the text editors example ( vi or emacs )

• 2. Save your file as name.cpp where name is the name of your file

• 3. Use one of the following ways to compile your program.

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Compile then Build

g++ -c hello.cpp // compile g++ hello.o -o hello // build

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The simple way

The standard way to compile this program is with the command

g++ hello.cpp -o hello This command compiles hello.cpp into an

executable program named "hello" that you run by typing 'hello' at the command line.

It does nothing more than print the word "hello" on the screen

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Compiling a program with multiplesource files

If the source code is in several files, say

"file1.cpp" and "file2.", then they can be compiled into an executable program named "myprog" using the following command:

g++ file1.C file2.C -o myprog

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Compile then Build multiple files

g++ -c file1.cpp

g++ -c file2.cpp

g++ file1.o file2.o -o myprog

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Basics of a Typical C++ Environment

Input/output• cin

• Standard input stream

• Normally keyboard

• cout• Standard output stream

• Normally computer screen

• cerr• Standard error stream

• Display error messages

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Ways to format the program

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Ways to format the program

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Variables and Data Types

A place in Memory To hold an information that a user use.

Deceleration

SpaceOccupied VariableName;

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C++’ Names

The name of a variable: • Starts with an underscore “_” or a letter, lowercase or uppercase, e.g.

_Students, pRice

• Can include letters, underscore, or digits. Examples are: keyboard, total_grade, _Score_Side1

• Cannot include special characters such as !, %, ], or $

• Cannot include an empty space

• Cannot be any of the reserved words

• Should not be longer than 32 characters (although allowed)

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Reserved Words

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Variables and Their Data Types

The amount of memory space necessary to store a variable is also referred to as a data type.

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Variables and Their Data Types

char 8 bits

short int • A group of 16 contiguous bits or 2 bytes, is used to

represent a natural number.

• ranges from –32768 to 32767.

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Example

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Practice -- what is the o/p

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Practice -- what is the o/p

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O/P

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Representing a Double-Word

Double-word combines 4 bytes, or 8 nibbles, or 32 bits. The bits, counted from right to left, start at 0 and end at 31.

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What are constants?

const PI = 3.14;

#define PI 3.14