Identifiers

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Identifiers

• Programmer defined names or words.
• Naming Rules for identifiers
• alphanumerical
• underscore
• no leading digit(s)
• no space

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Identifiers - Examples

• Correct
• RowCount
• Return2Copies
• columncount
• ColumnCount
• columnCount
• Incorrect Names
• 2Copies
• row Count
• 3rdRow

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Basic Concept of Programming

• Basic Computer Operations
• Data Inputs
• Data Manipulations
• Data Outputs

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Data Manipulation

• Manipulating Data with
• Unknown values
• user inputs
• depend on the results of other manipulations
• Known values predetermined
• Constant values values will not change thru
  the execution

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Data Storage

• Run time storage for unknown value
• Variable Identifier - Data Storage Reference
• names (identifier)
• data types (size of the data storage)
• scopes (duration or lifetime)

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Variable Name

• Naming Rules for Variables
• alphanumerical
• no leading digit
• no space
• underscore
• Naming Conventions
• lowercase for first character
• Uppercase for the character of a word

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Variable Name - Examples

• Correct Names
• RowCount
• Return2Copies
• columncount
• Preferred
• rowCount
• return2Copies
• columnCount
• Incorrect Names
• 2Copies
• row Count
• 3rdRow

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Data Types

• Primitive Data Types
• int
• char
• float

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Define a Variable

• Syntax
• Data_Type Variable_name
• Data_Type Variable_name Value
• Examples
• int iCount
• char iFirstCharacter
• char iC A
• int iNumber 0
• float fFlat 17.5

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Scope of a Variable

• Scopes
• block scope
• instance scope will talk more about this later
• class scope will talk more about this later

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Scope - block

• Scope
• between the most inner block of
• starts right after the definition of the variable

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Block Scope - Example
int iTotal int iSteps int iBegin 0 int
iEnd 10 //data manipulations //end of scopes
of iBegin and iEnd //data manipulations //end of
scopes of iSteps and iTotal
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Block Scope Example cont.
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Scope - instance

• Instance scope variables
• properties
• non-static

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Scope - class

• Class scope variables
• unique for all instances of the same class
• static variables

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More on Data Manipulations

• Basic operations
• value assignment operator
• addition operator
• subtraction operator -
• multiplication operator
• division operator /

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Simple statements
int iBegin 0 int iEnd 10 int iSteps int
iTotal iSteps iEnd iBegin iTotal 5
iSteps //note a complete statement ends with
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Basic Structures

• Structured Programming in C/C
• sequence
• decision/selection/testing
• iteration/repetition/looping

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Sequence
//Do this instruction
int iCount 0 int iRow 0 int iColumn 0
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Decision/Selection/Testing
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Iteration/Repetition/Looping