Concepts - Basics C Keywords

'C' - Keyword's

• In programming, a keyword is a word that is reserved by a program because the word has a special meaning.
• Keywords can be commands or parameters
• Every programming language has a set of keywords that cannot be used as variable names.
• Keywords are sometimes called reserved names.

'C' - Keyword's Categories/types.

• Data Types
• Qualifiers
• Loop
• Storage Class
• Decision
• Jump
• Derived
• User Defined
• Others

1. Keywords – Data Types

• char 

- The basic data type supported for storing characters of one byte size.

•  int 

- A variable would hold a integer type value

- A simple and efficient type for arithmetic operations

- Usually a word size of the processor although the compiler is free to choose the size.

- ANSI C does not permit an integer, which is less than 16 bits

• float

- A variable would hold a single precision value

- ANSI C does not specify any representation

• double

- A variable would hold a double precision value

- The implementations may follow IEEE formats to represent floats and doubles, and double occupies 8-bytes in memory, Supports 0, ∞ (-/+) and NaN

• signed

- A variable can hold both positive and negative value

- Most Significant Bit (MSB) of the variable decides the sign

• unsigned

- A variable can hold only positive value

- Larger range of positive values within the same available space

• short

- Fairly small integer type of value

• long

- Fairly large integer type of value

NOTE : ANSI C says that the size of short and long implementation defined, but ensures that the non-decreasing order of char, short, int, and long is preserved i.e.,

"char ≤ short ≤ int ≤ long"