C Overview

• History
• Dennis Richie, invented it, to write the Unix with it -> 1970
• Previously Unix was written by assembly -> Bad portability :(
• Rewrite Unix again for each new processor
• ANSI (American National Standardization Institute), released the first C standard in 1989 ( C89 )
• Amendment 1 was added to C89 in 1995
• C89 with Amendment 1 is the base of C++
• C89 with Amendment 1 is called the C Subset of C++
• C99 was released by ANSI in 1999
• Nearly the same as C89  + some added features (Such as: Variable Length Arrays and strict pointer qualifier)

• Middle Level Language
• High level features:
• C is like the High Level Language in the following features:
• Portable (easy to adapt the program written for a platform to another platform)
• Supports DataTypes
• A datatype defines
• A set of values that the variable can store
• A set of operations that can be performed on that variable
• C is unlike the High Level Languages in the following features:
• C does not support Run-Time Error Checking, like "array index out of bound"
• C is a Weakly typed language
• Implicit casting is allowed
• Implicit casting happens for arguments that does not match the parameter type.
• C has few keywords:
• 32 Keyword in C89
• 5 more Keywords in C99
• BASIC (a high level language) defined 100 keywords
• Low Level Features:
• Manipulation of Bits, Bytes and Addresses

C key words,  from "The Complete C Reference - 4th Edition"

• C is a Structured Language
• The code consists of component blocks (functions - while - if - ...etc )
• goto usage is either forbidden or discouraged
• Assembly is not a structured language, cause the code contains jumps and branches -> Spaghetti code!

• C is a programmer language
• Unlike BASIC language, which is developed for non-programmers to solve simple problems.

• Compiler Vs Interpreter
• Interpreter parses one line of code at a time, execute it.
• Compiler parses the whole program, generates machine code, that is executed.
• Interpreter parses the code line each time it is being executed
• Compiler parses the code lines only once.
• Java is designed for interpretation.
• C is designed for compilation (However we can make C interpreters, however will not best utilize C)