Introduction to Computers and Programming

What is a program?

Program is set of instructions that computer follows to perform a task.

Computers can perform a wide variety of tasks because they are ______

programmable

What is a computer?

a programmable electronic device that stores, retrieves, and processes a large quantity of data both quickly and accurately.

A computer is a system of ____ 

hardware and software devices/components 

the physical components of the computer are called _____

hardware

Main Hardware Component (5 Categories)

Central Processing Unit (CPU), Main memory, secondary storage devices, input devices, output devices

What is the central processing unit (CPU)?

The part of the computer that runs programs

The CPU is comprised of two components which are… 

Control unit, arithmetic and logic unit (ALU) 

The main memory is also called the….

Random Access Memory (RAM)

Main Memory is rapid-access, relatively low-capacity storage for the instructions and data of ______ programs

executing/running

Main memory is …… Data and instructions stored here are erased when the program terminates or the computer is turned off

volatile

Main memory is organized as follows (bit, byte) (Provide definitions)

bit: smallest piece of memory.  Has values 0 (off, false) or 1 (on, true); byte: 8 consecutive bits. Bytes have addresses.

What is an address?

Addresses – Each byte in memory is identified by a unique number known as an address.

What is secondary storage? Is it persistent (what does it mean?)

Secondary storage is long-term, high-capacity storage for programs and data not currently in use. Secondary storage is persistent (non-volatile); data is retained when the program stops running or the computer is turned off.

Input Definition

data the computer accepts from outside for processing

Output Definition

data the computer sends to the outside

Name the 2 categories of software

System software and Application software

Definition of System Software (3 examples)

programs that manage the computer hardware and the programs that run on them. Examples: operating systems, utility programs, and software development tools

Definition of Application Software (3 examples)

programs that provide services to the user. Examples: word processors, spreadsheets, image editing software, games, and other programs to solve specific problems

A program ….

a set of instructions that the computer follows to perform a task

An algorithm is …

a set of well-defined, ordered steps for performing a task or solving a problem

Machine language ….

numeric language understood by a computer processor (binary pattern)

Types of language + give definitions

Low-level: used for communication with computer hardware directly.  Often written in binary machine code (0’s/1’s) directly.

High-level: closer to human language

Compiler definition

Programs written in high-level languages must be converted to machine language for execution on a computer. (in C+)

integrated development environment

combines the tools needed to write, compile, and debug a program into a single software application

What is a Program Made of? (5 things)

• Key Words

• Programmer-Defined Identifiers

• Operators

• Punctuation

• Syntax

syntax

• The rules of grammar that must be followed when writing a program

• Controls the use of key words, operators, programmer-defined symbols, and punctuation

statement

a complete instruction that causes the computer to perform some action; Statements often occupy one line in the source code, but they can be spread over multiple lines.

• variable

• a named storage location in the computer’s memory for holding a piece of data.

• A variable can hold one data item at a time, but the data held can be changed (it can vary) while the program is running.

• A variable holds a specific type of data. There are types for holding: whole numbers, real numbers, single characters, and more.

To create a variable in a program you must write a variable definition

• A variable holds a specific type of data.

The word double 

specifies that the variables can hold double-precision floating point numbers. 

Three steps that programs typically perform:

1. Gather input data:

• From keyboard

• From files on disk drives

• From other hardware device

1. Process the input data

2. Display the results as output:

• Send it to the screen

• Write it to a file 

• Send it to another hardware device