Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy.

Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our Privacy Policy and User Agreement for details.

Like this document? Why not share!

1,775 views

Published on

No Downloads

Total views

1,775

On SlideShare

0

From Embeds

0

Number of Embeds

2

Shares

0

Downloads

61

Comments

0

Likes

3

No embeds

No notes for slide

- 1. Data Structures and Algorithms Constants and VariablesConstants @ a value, that is, a specific alphabetical and/or numeric value, that never changes during the processing of all the instructions in a solution @ can be any type of data - numeric, alphabetical, or special symbolsVariable @ may change during processing @ the computer sets up a specific memory location to hold the value of each variable name found in a program @ can be any data type, just as constantBeginning Problem-Solving Concepts for the Computer Page 1 of 17
- 2. Data Structures and Algorithms Constants and Variables Rules for Naming and Using Variables @ Name a variable according to what it reperesents, that is, HOURS for hours worked, PAYRATE for rate of pay, and so on. @ Do not use spaces in a variable name. If a space is needed, use the underline character. @ Do not use a dash (or any symbol that is used as a mathematical operator) in a variable name. The computer will recognize these symbols as mathematical operators, turn your variable into two or more variables, and treat your variable as a mathematical expression.Beginning Problem-Solving Concepts for the Computer Page 2 of 17
- 3. Data Structures and Algorithms Constants and Variables Rules for Naming and Using Variables @ After you have introduced a variable name that represents a specific data item, this exact variable name must be used in all places where the data item is used. @ Be consistent when using upper- and lowercase characters.Beginning Problem-Solving Concepts for the Computer Page 3 of 17
- 4. Data Structures and Algorithms Data TypesData @ unorganized factsInformation @ what is returned to the user as output, or processed data Input Data Output DATA Processed into REPORT Information Checks Calaculates Deposits Balance Sheet the balance Bk. Chgs.Beginning Problem-Solving Concepts for the Computer Page 4 of 17
- 5. Data Structures and Algorithms Data Types Data Type Data Set Examples Numeric: Integer All whole numbers 3570 , -54 All real numbers (whole + Numeric: Real decimal) 3792.91, 474526.23 CHARACTER (surrounded by All letters, numbers, and "A","a", "M", "1", quotation marks) special symbols "88","&", "#" STRING (surrounded Combinations of more by quotation marks) than one character "waahhh", "876860" LOGICAL TRUE FALSE TRUE FALSEBeginning Problem-Solving Concepts for the Computer Page 5 of 17
- 6. Data Structures and Algorithms Data Types Data Data Type The price of an item: 12.50, 34.00 Numeric: real An account number: "A8693" Character String A quantity: 10,345 Numeric: integer The name of a school: "STI" Character String A credit check: TRUE, FALSE Logical A date: 06/21/03 or "01/11/81 Date or Character StringBeginning Problem-Solving Concepts for the Computer Page 6 of 17
- 7. Data Structures and Algorithms Data TypesRules for Data Types@ The data that define the value of a variable or a constant will most commonly be one of three data types: numeric, character (including character string), or logical.@ The programmer designates the data type during the programming process. The computer then associates the variable name with the designated data type.@ Data types cannot be mixed.Beginning Problem-Solving Concepts for the Computer Page 7 of 17
- 8. Data Structures and Algorithms Data TypesRules for Data Types@ Each of the data types uses what is called a data set. The numeric data uses the set of all base 10 numbers, the plus sign (+), and the negative sign (-); the character type uses the set of data consisting of the words TRUE and FALSE. The use of any data outside the data set results in an error.@ Any numeric item that must be used in calculations resulting in a numeric results must be designated as numeric data type. All other numbers should be designated as character or character-string data types, even if data are all numbers.Beginning Problem-Solving Concepts for the Computer Page 8 of 17
- 9. Data Structures and Algorithms Functions @ small sets of instructions that perform specific tasks and return values @ usually built into a computer language or application @ used as parts of istructions in a solutionClasses of Functions: a Mathematical a String a Conversion a Statistical a UtilityBeginning Problem-Solving Concepts for the Computer Page 9 of 17
- 10. Data Structures and Algorithms Functions Example Result SQRT(4) 2 Mathematical ABS (-3) 3 ROUND (5.678) 6 INTEGER (5.789) 5 Example Result String MID(S, 3, 2) where S = "THOMAS" "OM" LEFT (S,3) where S = "THOMAS" "THO" RIGHT (S, 3) where S= "THOMAS" "MAS" LENGTH(S) where S = "THOMAS" 6Beginning Problem-Solving Concepts for the Computer Page 10 of 17
- 11. Data Structures and Algorithms Functions Example Result Conversion VALUE ("57") +57 STRING (+57) "57" Statistical Example Result AVERAGE (1,2,3,4) 2.5 MAX (1,2,3,4) 4 MIN (1,2,3,4) 1 SUM (1,2,3,4) 10 Utility Example Result DATE 6/22/03 TIME 2:55:03Beginning Problem-Solving Concepts for the Computer Page 11 of 17
- 12. Data Structures and Algorithms Operators @ the data connectors within expressions and equations @ tell the computer how to process the data @ tell the computer what type of processing (mathematical,logical or whatever) needs to be doneTypes of Operator @ Mathematical - include addition, subtraction, multiplication, division, integer division, modulo division, powers, and functions @ Relational - = , <, >, >=, <=, <> @ Logical - AND, NOT, and ORBeginning Problem-Solving Concepts for the Computer Page 12 of 17
- 13. Data Structures and Algorithms Operators Mathematical Operation Resultant 3.0 + 5.2 8.2 7.5 - 4.0 3.5 8.0 * 5.0 40 9.0/4.0 2 94 2 9 MOD 4 1 3^2 9 Relational Operation Resultant 3=2 FALSE 5>1 TRUE 5=1 FALSE 7 <= 8 TRUE 9>=12 FALSE 10 < 2 TRUE 8<>8 FALSEBeginning Problem-Solving Concepts for the Computer Page 13 of 17
- 14. Data Structures and Algorithms Operators Logical A Not A T F F T A B A AND B T T T T F F F T F F F F A B A OR B T T T T F T F T T F F FBeginning Problem-Solving Concepts for the Computer Page 14 of 17
- 15. Data Structures and Algorithms OperatorsHierarchy of Operations ( ) Reorders the hierarchy; all operations are completed within the parentheses using the same hierarchy. 1. Functions Mathematical: 2. Power 3. , MOD 4. *, / 5. +, - Relational: 6. =, <, >, <=, >=, <> Logical: 7. NOT 8. AND 9. ORBeginning Problem-Solving Concepts for the Computer Page 15 of 17
- 16. Data Structures and Algorithms Expressions and EquationsExpression @ processes data, the operands, through the use of operators @ example: LENGTH * WIDTHEquation @ stores the resultant of an expression in a memory location in the computer through the equal (=) sign @ example: AREA = LENGTH * WIDTH @ often called assignment statements because the variable on the left-hand side of the equal sign is assigned the value of the expression on the right- hand side @ the equal sign does not mean equals; instead it means replaced by or is assigned the value ofBeginning Problem-Solving Concepts for the Computer Page 16 of 17
- 17. Data Structures and Algorithms Expressions and EquationsBeginning Problem-Solving Concepts for the Computer Page 17 of 17

No public clipboards found for this slide

×
### Save the most important slides with Clipping

Clipping is a handy way to collect and organize the most important slides from a presentation. You can keep your great finds in clipboards organized around topics.

Be the first to comment