Introduction to Computers and C++ Programming

Computer program

A set of instructions for a computer to follow.

Computer software

The collection of programs used by a computer.

PCs (Personal Computer)

Relatively small computers used by one person at a time.

Workstation

Larger and more powerful than a PC.

Mainframe

Still larger than a workstation, requires support staff, and is shared by multiple users.

Networks

A number of computers connected to share resources, printers, devices, and information.

Input devices

Allows communication to the computer.

Output devices

Allows communication to the user.

Processor (CPU)

The main component that follows program instructions.

Main memory

Memory locations containing the running program.

Secondary memory

Permanent record of data often on a disk.

Binary Digit or Bit

A digit that can only be zero or one.

Byte

Each memory location has eight bits.

Address

Number that identifies a memory location.

Larger Data Items

Some data is too large for a single byte; most integers and real numbers are too large.

Data or Code

Interpretation of binary data depends on the current instruction.

File

Stores data or instructions in secondary memory.

Hard disk

Fast secondary memory, fixed in the computer and not normally removed.

Floppy disk

Slow secondary memory, easily shared with other computers.

Compact disk

Slower than hard disks, easily shared with other computers, can be read only or re-writable.

Random Access

Usually called RAM, allows the computer to directly access any memory location.

Sequential Access

Data is generally found by searching through other items first, more common in secondary memory.

Central Processing Unit (CPU)

Typically called the CPU, follows program instructions and performs operations like add, subtract, multiply, divide, and move data from location to location.

Operating System

A program that allows us to communicate with the computer, allocates the computer's resources, and responds to user requests to run other programs.

Common Operating Systems

Examples include UNIX, Linux, DOS, Windows, Macintosh, and VMS.

Computer Input

Consists of a program and some data.

High-level Languages

Programming languages that resemble human languages and are designed to be easy to read and write.

Examples of High-level Languages

C, C++, Java, Pascal, Visual Basic, FORTRAN, Perl, PHP, Lisp, Scheme, Ada, C#, Python.

Translation of High-level Languages

High-level languages must be translated to zeros and ones for the CPU to execute a program.

Low-level Languages

Languages that include assembly language, which must be translated to machine language (zeros and ones).

Assembly Language Command

An example is ADD X Y Z, which means add the values found at x and y in memory, and store the result in location z.

Machine Language

The language that the CPU can follow, represented in binary (e.g., 0110, 1001, 1010, 1011).

Compilers

Programs that translate high-level language to machine language.

Source Code

The original program written in a high-level language.

Object Code

The translated version of the source code in machine language.

Linkers

Programs that combine object code for the programs we write and object code for pre-compiled routines into a machine language program.

First Programmable Computer

Designed by Charles Babbage, began work in 1822, but was not completed in his lifetime.

First Programmer

Ada Augusta, Countess of Lovelace, a colleague of Babbage.

Algorithm

A sequence of precise instructions that leads to a solution.

Program

An algorithm expressed in a language the computer can understand.

Program Design Process

Includes the Problem Solving Phase and Implementation Phase.

Problem Solving Phase

Involves specifying the task completely, determining input and output, organizing output, and developing the algorithm before implementation.

Testing the Algorithm

Experience shows that testing the algorithm for correctness saves time in getting your program to run.

Implementation Phase

Translate the algorithm into a programming language.

Compile

Locates errors in using the programming language.

Run the program

Verify correctness of results.

Object Oriented Programming

Abbreviated OOP, used for many modern programs.

Encapsulation

Objects contain their own data and algorithms.

Inheritance

Objects can inherit characteristics from other objects.

Polymorphism

A single name can have multiple meanings depending on its context.

Software Life Cycle

Analysis and specification of the task (problem definition).

C++

Derived from the C language.

C

Developed by Dennis Ritchie at AT&T Bell Labs in the 1970s.

C++ History

C++ developed by Bjarne Stroustrup at AT&T Bell Labs in the 1980s.

Sample C++ Program

A simple C++ program begins with #include .

Variable Declaration

Identifies names of three variables to name numbers.

cout

Used for output to the monitor.

cin

Used for input from the keyboard.

Computation

Performs a computation using the '*' operator for multiplication.

Program Layout

Compiler accepts almost any pattern of line breaks and indentation.

Program Formatting

Programmers format programs so they are easy to read.

Braces Placement

Place opening brace '{' and closing brace '}' on a line by themselves.

Statement Indentation

Indent statements.

Single Statement per Line

Use only one statement per line.

Variable Declaration Location

Typically variables are declared at the beginning of the program.

Statement Terminator

Statements (not always lines) end with a semi-colon.

Include Directives

#include tells compiler where to find information about items used in the program.

iostream Library

iostream is a library containing definitions of cin and cout.

Namespace Usage

using namespace std; tells the compiler to use names in iostream in a 'standard' way.

Main Function Start

To begin the main function of the program, use int main() {.

Main Function End

To end the main function, use return 0;.

C++ Source Code

C++ source code is written with a text editor.

Compiler Function

The compiler on your system converts source code to object code.

Linker Function

The linker combines all the object code into an executable program.

C++11

C++11 (formerly known as C++0x) is the most recent version of the standard of the C++ programming language.

C++11 Approval Date

Approved on August 12, 2011 by the International Organization for Standardization.

C++11 Compiler Compatibility

C++11 language features are not supported by older compilers.

Compiling C++11

Check the documentation with your compiler to determine if special steps are needed to compile C++11 programs.

g++ Extra Flags

With g++, use extra flags of -std=c++11.

Running a Program

Obtain code in Display 1.10, compile the code, fix any errors the compiler indicates and re-compile the code, then run the program.

Bug

A mistake in a program.

Debugging

Eliminating mistakes in programs.

Logic Errors

Errors in the program's algorithm that are most difficult to diagnose.

Syntax Errors

Violation of the grammar rules of the language discovered by the compiler.

Run-time Errors

Error conditions detected by the computer at run-time.