Basic of Programming Language Skill Area 304.1

Computer System Computer Program Programming Language Programmer Translators

Computer System

Input Devices Processing (CPU/Memory) Output Devices Storage Devices

Also called CPU, processor or microprocessor “Brains” of the computer Performs all computer operations

Where all the input data and results stored o Random Access Memory (RAM) o Read Only Memory (ROM)

RAM is volatile = data are lost when computer is turned off Read current info and also write new info Very important in determining capabilities of the computer system Stores work when they are in use. o Word Document o Spreadsheet o Power Point

ROM is non-volatile = permanent and are not affected where computer is turned lost Can read info Stored in ROM Can not write new info into ROM Used for “internal workings” of computer –Boot Software

Computer Program

A program or computer program is a set of instructions that tells a computer how to perform a particular task. Programs are developed using programming language. Computer programming is the art of developing computer programs. Programming is rather like a recipe; describe the ingredients (the data) and the sequence of steps (the process)

A program is developed to help the activity of humans easier Examples: –Banks –Communication –Business –Medical Science –Education –Travel and Ticketing –Daily Life –etc

A programming language is a vocabulary and set of grammatical rules for instructing a computer to perform specific tasks Programming language provides a set of rules to develop a program.

A Programmer is a person who writes a computer program. The job of programmer is to convert a solution to a problem into set of instructions understood by a computer. The programmer should test the program to see whether it is working. Corrective actions should be taken if not working properly.

When we want to write a program to solve a problem, the hardest is to know how to start, we also need to work out the steps to take for reaching the solution, we also need to be sure that the program works without errors, according to the specifications.

Three good reasons for learning programming: –Programming helps you understand computers. –Writing a few simple programs increases your confidence level. –Learning programming lets you find out quickly whether you like programming and whether you have the analytical turn of mind programmers need.

Three types of Programming Language –Machine Language –Assembly Language –High-Level Language

The lowest and most elementary level of Programming Language. 1 st type of PL to be developed. Represented inside the computer by a String of binary digits (bits) 0 and 1. The symbol 0 stands for the absence of Electric Pulse and 1 for the presence of an electric pulse

Their order tells the computer what to do. All other kinds of software need to be translated into machine code before they can be used.

Symbolic instruction what humans can understand Form of alphanumeric symbols known as mnemonic codes. Can have maximum up to 5 letter combination E.g. –ADD for addition –SUB for subtraction

Maps directly into machine language Designed for a family of microprocessors MOV AX, BX ADD AX, 5A INC BX JMP Compile

High-Level language is basically symbolic languages that use English words and/or mathematical symbols rather than mnemonic codes. Each instruction in the high-level language is translated into many machine language instructions.

To enable people (programmer) to write program easily and in their own native language environment (English). Examples: –C, C++, Java, VB, HTML

Languages have been developed for general purpose and specific purpose Types of High-Level Languages: –Algebraic Formula-Type Processing –Business Data Processing –String and List Processing –Object Oriented Programming Language (OOP) –Visual Programming Language

Translators

Types of Programming Language Translators: –Assembler –Interpreter –Compiler

To convert the assembly language into machine code. Translate mnemonic operation codes to their machine language equivalents.

A computer program that executes instructions written in a programming language and do not produces the executable file. Interpreter: o Checks the keywords of a program o Taking one instruction at a time and convert it into machine language before taking upon the next instruction. Examples of interpreter based language: o PHP, JavaScript, BASIC

A program that changes source code (high- level language) to object code which that can be executed by a machine. Compiler: o Checks syntax of program o Checks at a time all the program Primary reason for compiling source code is to create an executable program Examples of compiler based language: C, C++, JAVA

Executables: Files that actually do something by carrying out a set of instructions. E.g.,.exe files in Windows Once the executable is there, it can be called by the user to process the given inputs to a program and produce the desired outputs.

Computer System (CPU, Main Memory, Keyboard, Mouse, etc) Computer Program a set of instructions that tells a computer how to perform a particular task. Programming Language a vocabulary and set of grammatical rules for instructing a computer to perform specific tasks Programmer - a person who writes a computer program Types of PL Machine Language Assembly Language High-Level Language Translators Interpreter Assembler Compiler