COP1220/CGS2423 Introduction to C++/ C for Engineers Professor: Dr. Miguel Alonso Jr. Fall 2008

Outline Why Program? Computer Systems: Hardware and Software Programs and Programming Languages What is a Program Made of? Input, Processing, and Output The Programming Process Procedural and Object-Oriented Programming

Why Program? What does a computer do? It is useful because it can be programmed, or told to do many different tasks. They are tools that make almost every profession easier to do. A computer is a machine specifically designed to follow instructions.

Why Program? Programs are called software, or a set of instructions that tells a computer what to do. Programs in the real world consist of the following: Logical flow of instructions Mathematical procedures Appearance on the screen The way the information is presented to the user The programs “user-friendliness” Manuals and other written documentation

Computer Systems: Hardware and Software Starting out with C++, Pearson, (2006)

Computer Systems: Hardware and Software Starting out with C++, Pearson, (2006)

Computer Systems: Hardware and Software CPU: Controls the computer’s operations and performs arithmetic functions Main Memory: Random Access Memory, or RAM, is the part of a computer that temporarily holds or stores information Consists of cells and bits (a “switch” that can be a 0 or 1 Each Cell has 8 bits, or a byte. Each cell is assigned a location number called an address.

Computer Systems: Hardware and Software

Other Devices Secondary Storage: Hard Disk, USB Stick Input Devices: Any devices that help the computer collect information from the outside world Output Devices: Devices that presents the computer’s information to the outside world.

Software Generally two categories of software in a computer: Operating system Application Software Single Tasking Multi-Tasking Single-User Multi-User

Programs and Programming Languages Computer Program: Set of instructions that tells a computer how to solve a problem or perform a task Algorithm: A set of well defined steps for performing a task or solving a problem A computer only understands 0’s and 1’s Programming Languages were invented to ease the task of programming Examples of Languages: C/C++, C#, JAVA

Programming Languages Low Level vs High Level Your very first program!

Source Code, Object Code, and Executable

What is a program made of? Language Elements

Lines, Statements, and Variables Line: single line as it appears in the body of the program (can be empty) Statement: complete instruction that causes the computer to perform an action Variable: named storage location in the computers memory for holding a piece of information. Usually stored in RAM. Variable definition/declaration Not the same thing! There are generally two types of variables: numbers and characters. Number: used to compute Characters: used for display