01computer programming concepts

8/2/2019 01Computer Programming Concepts

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COMPUTERPROGRAMMING

CONCEPTS

School of Engineering & Architecture

COMP1 AL

7/30/2010

jnb


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Computer science discipline dealing withthe creation and maintenance of computerprograms.

One activity in the complex field of softwareengineering

COMPUTER PROGRAMMING


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SOFTWAREprograms or instructions thatmake the computer work.

TYPES

1. System Software

2. Applications Software


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PROGRAMMING LANGUAGEspecial-purpose language used to create and

maintain programs

specified by a well-defined set of rules syntax(grammar): specifies ways in which

language elements can be combined to create validprograms

semantics (meaning): specifies how a programbehaves

programming language rules are more strictthan natural language rules


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PROGRAMMING LANGUAGE(CATEGORIES)

by level - how close the instructions are toML

high-level language (HLL): human-like; usesEnglish-like terms; one HLL instruction = manyML instructions

low-level language (LLL): machine-like; usesmnemonics or opcodes; almost one-to-oneinstruction correspondence between LLL and ML


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MACHINE LANGUAGE (ML) native language of a computer

ML is made up of very simple instructions. (addtwo numbers, jump to a program statement, fetchdata from memory, store data to memory, etc.)

computers are powerful since they execute millionsof ML per second.

ML is machine readable but is typically not readily

understandable by humans.


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MACHINE LANGUAGE (ML)-programming the computer by entering only the binary/

hexadecimal operation codes.

BINARY CODE HEX CODE COMMENTS

00111110 00110010 3E 32 // LOADACCUMULATOR

WITH 32H

11010011 00000101 D3 05 // OUTPUTTHE CONTENTTO PORT 5

01110110 76 // HALT


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LOW LEVEL LANGUAGE

Assembly Language- Mnemonics (abbreviations for the instruction operation

codes-[opcodes]) are being entered in programming the

computer.

MNEMONICS COMMENTS

MVI A, 32H LOAD ACCUMULATOR WITH 32H

OUT 5 OUTPUT THE CONTENTS TO I/O

PORT 5

HLT HALT


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HIGH LEVEL LANGUAGE

Pascal Languagevar

x, y, z : integer;

begin

x := 10;

y := 3;

if y 0 thenz := x div y;

end.


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HIGH LEVEL LANGUAGE

BASIC Language10 INPUT N1,N2

20 PRINTSUM = ; N1 + N2

30 END


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HIGH LEVEL LANGUAGE

C Language

# include

# includemain(){

printf(Hello World!);

getch();}


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HIGH LEVEL LANGUAGE

Java Language

public class gg {

public static void main(String[] args) {

System.out.println("Hello World!");

}}


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PROGRAM TRANSLATIONconversion of a program (called the source

code) written in some programminglanguage to its equivalent program (calledexecutable, or object code) in the

machine language of a target computerILLUSTRATION:

ML

1110111011

PROGRAMTRANSLATION

SOURCE

CODE

IN


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PROGRAM TRANSLATION

categories:

compilers: translates an entire

source code(high level languageprogram) to the equivalent object orexecutable code

assemblers: translates assemblylanguage to ML

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