Download Chapter 1: Introduction - CS 241 (c++)

CHAPTER 1: INTRODUCTION
C++ Programming
CS 241
Course URL:
• http://241cs.wordpress.com/
Text Book:
• C++ How to Program, DETITEL & DEITEL, eighth Edition
or seventh Edition
• C++ Without Fear A Biggener's Guide That Makes You
Feel Smart, Brian Overland
GRADES
Grading
• First Midterm: 10
• Second Midterm:15
• Lab quize:5
• Homework:5
• Participation and Evaluations:5
• Final: 40
• Final Lab: 20
Course Syllabus
TOPICS
Introduction
Programming basics(data types, variables, assignment, operators)
Program flow (control statements and looping)
Functions
Arrays
Pointers
Recursive functions
Introduction to mathematical software packages
Simple mathematical problem solving using the chosen software package
What is a Computer?
Computer
• is a device that can perform computations and make logical decisions
billions of times faster than human beings can.
Computer programs
• Sets of instructions that control computer’s processing of data
Hardware
• Various devices comprising computer
• Keyboard, screen, mouse, disks, memory, CD-ROM, processing units,
Software
• Programs that run on computer
*Computers (often referred to as hardware) are controlled by software
Programming Languages
Computer languages may be divided into three general types:
1.
2.
3.
Machine languages
Assembly languages
High-level languages
Programming Languages
1- Machine language:
• Only language computer directly understands
• Consist of strings of numbers 1s and 0s.
• Machine language is often referred to as object code.
Programming Languages
2- Assembly language
• English-like abbreviations that represent elementary operations
• Clearer to humans
• Translator programs called assemblers convert assembly-language
programs to machine language.
• Programmers still had to use many instructions to accomplish even
the simplest tasks.
• Example:
MOV AL , #61h
Programming Languages
3- High-level languages
• Similar to everyday English
• Single statements accomplish substantial tasks
• Translator programs called compilers convert high-level language
programs into machine language
Terms
Source code
• is a program in a form suitable for reading and writing by a human
being
Executable program (executable)
• is a program in a form suitable for running on a computer
Compilation
• is the process of translating source code into object code
Compiler
• is a program that performs compilation as defined above
The object code file
• contains a sequence of instructions that the processor can
understand but that is difficult for a human to read or modify.
Typical C++ Development Environment
C++ systems generally consist of three parts:
• a program development environment, the language and the C++
Standard Library.
C++ programs typically go through six phases:
1.
2.
3.
4.
5.
6.
edit
preprocess
compile
link
load
execute
Editor
Disk
Program is created in
the editor and stored
on disk.
Preprocessor
Disk
Preprocessor program
processes the code.
Disk
Compiler creates
object code and stores
it on disk.
Compiler
Linker
Disk
Primary
Memory
Linker links the object
code with the libraries,
creates a.out and
stores it on disk
Loader
Loader puts program
in memory.
Disk
..
..
..
Primary
Memory
CPU
..
..
..
CPU takes each
instruction and
executes it, possibly
storing new data
values as the program
executes.
More details …
Edit
•
Programmer writes program (and stores source code on disk)
Pre-process
•
Perform certain manipulations before compilation
Compile
•
the compiler translates the C++ program into machine-language
code (also referred to as object code).
More details …
Link
• A linker perform the link operation to produce an executable
program.
Load
• Before a program can be executed, it must first be placed in memory.
• This is done by the loader, which takes the executable image from
disk and transfers it to memory.
Execute
• the computer, under the control of its CPU, executes the program one
instruction at a time
First Program in C++: Printing a Line of
Text
First Program in C++: Printing a Line of
Text (cont.)
Comments
• Document programs
• Improve program readability
• Ignored by compiler
• Single-line comment
 Begin with //
• Multiple-line comment
• Begin with /* end with */
First Program in C++: Printing a Line of
Text (cont.)
preprocessor directive
• Lines that begin with # are processed by the preprocessor
before the program is compiled.
• #include <iostream> notifies the preprocessor to include in the
program the contents of the input/output stream
• Must be included for any program that outputs data to the
screen or inputs data from the keyboard
Standard Library
Rich collections of existing code that can be reused in
your applications
Common math calculations e.g. sqrt
2. String manipulations
1.
3.
Character manipulations
4.
Input/output
5.
Error checking
* Provided as part of the C++ development environment •
iostream library
• part of the C++ Standard Library
• provides a uniform way of handling input from (and output to)
predefined sources
iostream library commands:
•
Standard Input Stream (cin) - Normally keyboard
•
Standard Output Stream (cout)- Normally computer screen
•
Standard Error Stream (cerr) - Display error messages
First Program in C++: Printing a Line of
Text (cont.)
• main is a part of every C++ program.
• The parentheses after main indicate that main is a program
•
•
•
•
building block called a function.
C++ programs typically consist of one or more functions and
classes.
Exactly one function in every program must be named main.
C++ programs begin executing at function main, even if main is
not the first function in the program.
The keyword int to the left of main indicates that main “returns”
an integer value.
• A keyword is a word in code that is reserved by C++ for a
specific use.
• For now, simply include the keyword int to the left of main in
each of your programs.
First Program in C++: Printing a Line of
Text (cont.)
• A left brace, {, must begin the body of every function.
right brace, }, must end each function’s body.
A statement normally ends with a semicolon (;), also known as
• A corresponding
•
the statement terminator.
• Preprocessor directives (like #include) do not end with a
semicolon.
First Program in C++: Printing a Line of
Text (cont.)
• The notation
std::cout specifies that we are using a name, in
this case cout, that belongs to “namespace” std.
• The names
cin (the standard input stream) and cerr (the
standard error stream) also belong to namespace std.
• The
<< operator is referred to as the stream insertion
operator
First Program in C++: Printing a Line of
Text (cont.)
• The characters
\n are not printed on the screen.
• The escape sequence \n means newline.
• Causes the cursor to move to the beginning of the next line
on the screen.
return statement is used at the end of main the value
0 indicates that the program has terminated successfully.
• When the
• According to the C++ standard, if program execution reaches
the end of main without encountering a return statement, it’s
assumed that the program terminated successfully—exactly as
when the last statement in main is a return statement with the
value 0.
Modifying Our First C++ Program
Modifying Our First C++ Program