# Expression. Arithmetic Operators +, -, *, /, ^, ( ) Evaluating an expression –Examples: 4 + 2 – 1 4 + 2 * 3 3 – 4 / 2 8 / 4 * 2 2 * 3 ^ 2 (2 * 3) + 2.

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Expression

Arithmetic Operators +, -, *, /, ^, ( ) Evaluating an expression –Examples: 4 + 2 – 1 4 + 2 * 3 3 – 4 / 2 8 / 4 * 2 2 * 3 ^ 2 (2 * 3) + 2 ^ 3

Order of Evaluation OperatorMultiples 1 ( )Inner to outer, left to right 2. ^left to right 3. *, /left to right 4. +, -left to right

Formula to Expression

((A+B))*2

Expression to Formula A / B * C - 2 A + B * C ^ D (A + B / (C – 2)) ^ D + 1 Evaluating an expression: 4 * 2 + 8 / 4 * 2 ^ 2 – 1 18 / 3 ^ 2 * (1 + 2)

Example Note: PV = f (FutureValue, IntRate, Years) Independent variables, dependent variable

Text Operator Concatenation: & –Join two or more text values into a single text value.

Number and Text Are Not Compatible ‘1 is different from 1. #VALUE –Blank and space are different.

Data Representation Digitizing: –Data, image, video, music –Digital smell Binary digit: Bit –0, 1

Text Data Text (Character, String) –Letters, digits, other symbols Coding schemes: –ASCII: 8 bits (byte), 256 characters “1” : 0110 0001 The code for “A” is different from “a”. –EBCDIC: 8 bits –UniCode: 16 bits, 65536 characters

Numeric Data Integer: Binary number 1: 0000 0001 Real: Floating number 123.456 ->.123456 * 10^3

Case Sensitive/Insensitive Many computer systems are case sensitive: –Operating systems: Unix, Linux –Programming languages: Java, C++, C# –Database: XML –Demo: Telnet:libra.sfsu.edu Username, Password

Comparing Text Data Collating sequence: the ordering of characters: –Blank –Digits in numerical order –Upper case letters in alphabetical order –Lower case letters in alphabetical order To compare two texts: –From left to right –Character for character

Examples “JEAN” < “JOHN”:True/False “John” < “Johny”:True/False “1234” < “45”:True/False Arrange “alan”, “Chao”, “JOHN” in ascending order: Arrange P1, P3, P10, P15, P20 in ascending order: Oracle database demo: Telnet: libra.sfsu.edu –Select * from Cust; –Select * from Cust Order by Cname;

Excel is Case Insensitive Order: –Blank –Digits in numerical order –Letters in alphabetical order Data/Sort/Options/Case Sensitive: –a<A<b<B<c<C …..

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