1. Advanced Programming Basics
Constants, Declarations, and Definitions
Advanced Programming Basics

2. C++ Program Elements
C++ C
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CSCI 240: Computing II

3. Lexical Tokens Character Set Keywords Identifiers Constants
Literal Strings
Operators
Punctuators
Special Characters
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CSCI 240: Computing II

4. C++ Character Set a -- z A -- Z 0 -- 9 , . ; : ? ! ' " ( ) [ ]
{ } < > | / \ ~ + - = # % & ^ *
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CSCI 240: Computing II

5. Identifiers
Name to denote Object, Function, Tag, typedef, Label or Macro
First character is alpha, followed by any number of alpha, numerals or an underscore. (Leading _ reserved for internal use.)
Case sensitive
Reserved words cannot be used
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CSCI 240: Computing II

6. Attributes of Identifiers
Type
Visibility (Scope)
Uniqueness (Linkage)
Permanence (Duration)
Storage Class
Qualifier (Modifiability)
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CSCI 240: Computing II

7. Type
Fundamental -- int, char, float, double, long, short, signed, unsigned
Derived -- arrays, functions, pointers, references, classes, unions, structures, enumerations
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CSCI 240: Computing II

8. Scope An Identifier can be Used within its Scope
File Scope – Global (C)
Class Scope -- Member of a Class (C++)
Function -- Labels (C)
Local -- Inside a Block (C)
11/19/2018
CSCI 240: Computing II

9. Linkages Bindings between identifiers External
“extern” – not local to a file (means not allocated here)
Internal
local to a file – e.g., “static”
No linkage
e.g., classes, enumerations – must be unique across all files (#ifndef, #define, #endif used to control this)
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CSCI 240: Computing II

10. Storage Duration Static
Storage assigned once before the program startup, initialized only once, exists throughout the program
Automatic
Storage assigned in a block, their status is completely undefined after the completion of the block where they were defined
11/19/2018
CSCI 240: Computing II

11. Storage Class Auto – default – automatic variables
Extern – external objects
Register – internal auto variables stored in hardware registers – fast access (advisory)
Static – in a block, a file or a class
11/19/2018
CSCI 240: Computing II

12. Qualifiers No qualifier – default – alteration allowed
Const – no alteration is allowed
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CSCI 240: Computing II

13. Acknowledgements
These slides were originally produced by Rajeev Raje, modified by Dale Roberts.
11/19/2018
CSCI 240: Computing II