Data representation

data representation
this is related to computers

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2. Data representation PRESENTED BY: PRASHANT SAURABH KESHAV JHA VIKASH TIWARY PAYAL SURBHI SONI

3. What is data representation? Data representation  refers to the internal method used to represent various types of  data  stored on a computer. Computers use different types of numeric codes to represent various forms of  data , such as text, number, graphics and sound .

4. Number system Non-positional number systems Use symbols such as I for 1, II for 2, III for 3, IIII for 4, IIIII for 5, etc. Each symbol represents the same value regardless of its position in the number Symbols are simply added to find out the value of a particular number Difficult to perform arithmetic with such a number system

5. Positional number systems Use only a few symbols called digits These symbols represent different values depending on the position they occupy in the number The value of each digit is determined by: The digit itself The position of the digit in the number The base of the number system ( base = total number of digits in the number system ) The maximum value of a single digit is always equal to one less than the value of the base

6. NUMBER SYSTEMS USED IN COMPUTER Decimal number system Binary number system Octal number system Hexadecimal number system

7. DECIMAL NUMBER SYSTEM A positional number system Has 10 symbols or digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9). Hence, its base = 10 Each position of a digit represents a specific power of the base (10) Can represent any number by using the available digits and arranging them in various positions

8. BINERY NUMBER SYSTEM ▪ A positional number system ▪ Has only 2 symbols or digits (0 and 1). Hence base = 2 ▪ The largest single digit is 1 (one less than the base) ▪ Each position of a digit represents a specific power of the base (2) Bit stands for binary digit ▪ A bit means either a 0 or a 1, n-bit number is a binary number consisting of ”n‘ bits ▪ Computer stores numbers, letters, and other special characters in binary form

9. OCTAL NUMBER SYSTEM A positional number system Has total 8 symbols or digits (0, 1, 2, 3, 4, 5, 6, 7). Hence, its base = 8 The largest single digit is 7 (one less than the value of the base) Each position of a digit represents a specific power of the base (8) Since there are only 8 digits, 3 bits (23 = 8) are sufficient to represent any octal number in binary

10. HEXADECIMAL NUMBER SYSTEM A positional number system Has total 16 symbols or digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F). Hence its base = 16 The symbols A, B, C, D, E and F represent the decimal values 10, 11, 12, 13, 14 and 15 respectively The largest single digit is 15 (one less than the value of the base) Each position of a digit represents a specific power of the base (16) Since there are only 16 digits, 4 bits (24 = 16) are sufficient to represent any hexadecimal number in binary

11. DATA TYPES Alphanumeric Data is a string of symbols where a symbol may be one of the letters A, B, C, ..., Z, or one of the digits 0, 1, 2, ..., 9, or a special character, such as + - * / , . ( ) = etc. Alphabetic Data consists of only the letters A, B, C, ..., Z, and the blank character Numeric Data consists of only numbers 0, 1, 2, ..., 9 Computers use binary numbers for internal data representation Group of bits used to represent a symbol is called a byte . 8- bits together make a byte Commonly used computer codes are BCD, EBCDIC, and ASCII

12. BINARY ARITHMATIC Data is handled in the computer by electronic/electrical components Electronic components operate in binary mode (can only indicate two states œ on (1) or off (0) The binary number system has only two digits (0 and 1), computer circuits only have to handle two binary digits Arithmetic rules/processes possible with binary numbers

13. UNICODE Why Unicode? No single encoding system supports all languages Different encoding systems conflict Universal character-encoding standard used for representation of text for computer processing —Provides a unique number for every character, no matter what the platform, no matter what the program, no matter what the language“

14. UNICODE FEATURES Provides a consistent way of encoding multilingual plain text Defines codes for characters used in all major languages of the world Defines codes for special characters, mathematical symbols, technical symbols, and diacritics Capacity to encode as many as a million characters Assigns each character a unique numeric value and name Reserves a part of the code space for private use Affords simplicity and consistency of ASCII, even corresponding characters have same code Specifies an algorithm for the presentation of text with bi- directional behavior Has lot of room to accommodate new characters, its growth process is strictly additive

15. UNICODE CHARACTERS Simple Characters Composite characters Duplicate characters in multiple languages Glyphs

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