FUNDAMENTALS OF 'C' LANGUAGE AND COMPUTERS

FUNDAMENTALS

COMPUTER :- IT IS AN ELECTRONIC DEVICE, WHICH IS USED TO PERFORM CALCULATIONS. IT TAKES INPUT FROM THE USER, PROCESS IT AND FINALLY PRODUCES OUTPUT TO THE USER.

INPUT :- IT IS A REQUEST / INSTRUCTION / COMMAND TO THE COMPUTER WHICH IS GIVEN BY THE USER.

INPUT DEVICES :- KEYBOARD, MOUSE, SCANNER

OUTPUT :- IT IS RESPONSE FROM THE COMPUTER TO THE USER.

OUTPUT DEVICES :- MONITOR / SCREEN / CONSOLE / VDU (VISUAL DISPLAY UNIT), PRINTER, PLOTTER

CPU :- IT STANDS FOR CENTRAL PROCESSING UNIT, WHICH IS THE HEART OF THE SYSTEM. ALL OPERATIONS ARE DONE IN CPU. IT CONTAINS 3 SUB UNITS AND THOUSANDS OF SUB SUB UNITS.

1) MU 2) CU 3) ALU

MU :- IT STANDS FOR MEMORY UNIT, WHICH STORES INFORMATION.

ALU :- IT STANDS FOR ARITHMETIC LOGICAL UNIT, WHICH PERFORMS ALL CALCULATIONS.

CU :- IT STANDS FOR CONTROL UNIT, WHICH CONTROL ALL OTHER UNITS.

COMPUTER / SYSTEM :- IT IS A COMBINATION OF HARDWARE AND SOFTWARE. BOTH HARDWARE AND SOFTWARE ARE INTERDEPENDENT.

HARDWARE :- WHICH ARE PHYSICALLY VISIBLE PARTS OF THE COMPUTER.

EX :- KEYBOARD, MOUSE, MONITOR

SOFTWARE :- WHICH ARE PHYSICALLY NOT VISIBLE TO THE USER. SET OF PROGRAMS, WHICH ARE USED TO RUN COMPUTER PROPERLY.

DATA :- IT IS NOTHING A KNOWN VALUE, WHICH IS FORMED WITH ALPHABETS / DIGITS / SPECIAL CHARACTERS.

INSTRUCTION :- IT IS A ORDER TO THE COMPUTER GIVEN BY THE USER.

PROGRAM :- SET OF INSTRUCTIONS.

WHY WRITE PROGRAM ? :- TO SOLVE PROBLEMS.

LANGUAGE :- IT IS USED TO WRITE PROGRAMS.

SOFTWARE :- SET OF PROGRAMS.

SYSTEM LANGUAGE :- COMPUTER HAVE A SPECIAL LANGUAGE CALLED MACHINE LANGUAGE / BINARY LANGUAGE. IT CAN'T UNDERSTAND OTHER LANGUAGES. MACHINE LANGUAGE CONTAINS ONLY ZEROS AND ONES. EVERY INSTRUCTION GIVEN BY THE COMPUTER IS TRANSLATED INTO ZEROS AND ONES. FOR EXAMPLE 25 IS CONVERTED INTO 11001.

TYPES OF LANGUAGES

1)  LOW LEVEL LANGUAGES

(MACHINE DEPENDENT LANGUAGES)

2)  HIGH LEVEL LANGUAGES

(MACHINE INDEPENDENT LANGUAGES)

TYPES OF LOW LEVEL LANGUAGES

1) MACHINE LANGUAGE

2) ASSEMBLY LANGUAGE

MACHINE LANGUAGE :- IT IS NOTHING BUT SYSTEM LANGUAGE, WHICH CONTAINS ALL ZEROS AND ONES. IT IS SYSTEM FRIENDLY LANGUAGE. THERE IS NO READING AND DEBUGGING (CORRECTING MISTAKES) FACILITIES IN THIS LANGUAGE. THE ONLY ADVANTAGE OF THIS LANGUAGE IS SYSTEM CAN UNDERSTAND DIRECTLY THIS LANGUAGE INSTRUCTIONS AND EXECUTES QUICKLY.

ASSEMBLY LANGUAGE :- IT CONTAINS MNEMONICS (SMALL ENGLISH WORDS) WHICH ARE USED TO PERFORM ARITHMETICAL, RELATIONAL AND LOGICAL OPERATIONS.

TYPES OF HIGH LEVEL LANGUAGES

1) STRUCTURE ORIENTED LANGUAGE

2) OBJECT ORIENTED LANGUAGE

HIGH LEVEL LANGUAGE :- ENGLISH IS THE MAIN FEATURE OF THIS LANGUAGE. IT IS USER FRIENDLY LANGUAGE. THERE IS EXCELLENT READING AND DEBUGGING (CORRECTING MISTAKES) FACILITIES IN THIS LANGUAGE. THE ONLY DISADVANTAGE OF THIS LANGUAGE IS SYSTEM CAN'T UNDERSTAND DIRECTLY THIS LANGUAGE INSTRUCTIONS AND EXECUTES SLOWLY.

TYPES OF LANGUAGE TRANSLATORS

1) ASSEMBLER

2) INTERPRETER

3) COMPILER

ASSEMBLER :- IT IS USED TO TRANSLATE ASSEMBLY LANGUAGE INSTRUCTIONS INTO MACHINE LANGUAGE.

INTERPRETER :-  IT IS USED TO TRANSLATE HIGH LEVEL LANGUAGE INSTRUCTIONS INTO MACHINE LANGUAGE (LINE BY LINE) (TIME WASTE).

COMPILER :-  IT IS USED TO TRANSLATE HIGH LEVEL LANGUAGE INSTRUCTIONS INTO MACHINE LANGUAGE (TOTAL PROGRAM AT A TIME) (TIME SAVE).

NOTE :- NOW A DAYS, ALL HIGH LEVEL LANGUAGES HAVE COMPILER.

STAGES OF PROBLEM SOLVING

1) ANALYZE THE PROBLEM

2) WRITE ALGORITHM

3) DRAW FLOW CHART

4) WRITE PROGRAM

ALGORITHM :-  IT CONTAINS STEP BY STEP PROBLEM SOLVING STATEMENTS IN ENGLISH LANGUAGE.

           TOKENS / BUZZ WORDS OF 'C' LANGUAGE

1) COMMENTS

2) WHITE SPACES

3) CHARACTER SET

4) KEY WORDS / RESERVED WORDS

5) CONSTANTS

6) VARIABLES

7) IDENTIFIERS

8) DATA TYPES