What is the difference between top down approach and bottom up approach in programming languages?

• A programming language is nothing but a language designed to communicate to machines through instructions and commands.
• Normally machines are computers. Programs are written using some programming languages to control the behaviour of machines/computers and to make them to perform required tasks.
• Programming language example: Assembly language, C language, C++ language, Java, C#, .NET, Python etc.

• C89/C90 standard – First standardized specification for C language was developed by American National Standards Institute in 1989. C89 and C90 standards refer to the same programming language.
• C99 standard – Next revision was published in 1999 that introduced new futures like advanced data types and other changes.
• C11 standard adds new features to C and library like type generic macros, anonymous structures, improved Unicode support, atomic operations, multi-threading, and bounds-checked functions. It also makes some portions of the existing C99 library optional, and improves compatibility with C++.

• Reliability
• Portability
• Flexibility
• Interactivity
• Modularity
• Efficiency and Effectiveness

• Embedded C is the extension of C programming language.
• Embedded C is used to develop micro controller based applications.
• Embedded C includes features not available in normal C like fixed-point arithmetic, named address spaces, and basic I/O hardware addressing.
• Cell phones, MP3 players are some example for embedded systems in which embedded C is used to program and control these devices.

• C language is belonging to middle level language. C language behaves as a bridge between machine level (low level) languages and high level languages.
• C language is more user friendly than machine level languages. And, C language does not support all the concepts that high level languages offer. So, C programming language is called as middle level language. 

High-level languages –

• These level languages provide almost everything that the programmer might need to do as already build into the language.
• Example: Java, Python

Middle-level languages –

• These languages don’t provide all the built-in functions found in high level languages, but provide all building blocks that we need to produce the result we want.
• Example: C, C++

Low-level languages –

• These languages provide nothing other than access to the machine’s basic instruction set.
• Example: Assembly language.