Execution Of C Or C++ Program With Real Life Example

Introduction:

In this article we will discuss the execution of C or C++ program with real life example. The following diagram shows the execution process of C / C++ program execution:



Preprocessor

• It accept source code as input (which is in human understandable format) & gives output as expanded code.
• It provides the ability for the inclusion of header files, macro expansion, conditional compilation & line control.
  
  
  1. To remove white space
  2. Header file inclusion
  3. Line spicing
  4. Each comment is replace by a single space character & new line characters are retained.
  5. Hello.i means interpreter(i) – is a translator that converts the statement written in high level language into equivalent statement in machine level language one by one.

Compiler

• Compiler is a program which is used for translating source code from high level language (C,C++) to lower level language (assembly language, machine language).
• In this case we consider that output is in assembly language having extension .asm
• Code generated by compiler is dependent means translate source code to assembly code.
  
  1. Parsing – to check whether semicolon is missing or not.
  2. Tokenizing - to create meaningfully statements a++ => a+1.
  3. Syntax analysis
  4. Symantec analysis – to check logic
  5. Code Optimization
     

Assembler

• It is a program which translates assembly language program to an object file, which contains code in machine language.
• Object file contains machine code but still it is non executable having extension .obj
• This code is not pure executable code & it will look like the following,
  
  101011100101000101010
  010011010011101100010
  110101100101010101100

Linker

• It is a program which accepts input as a object code of our program.
• It can take more than one object files & combined them into a single executable program having extension .exe
• Output of this phase is executable file ready for execution.
• Linker adds primary header over executable file which contains:
  
  1. Address of entry point
  2. Magic number
  3. Date Time stamp

Loader

• Loader is a program which is part of operating system that is responsible for loading programs.
• It places program in memory (RAM) & prepares them for execution.
• Loading a .exe file from HDD to RAM means magnetic address space to electric address space.
• In this phase we get output of our program.

Real Life Example:

• Suppose we like to order LCD TV from XYZ Company. Now suppose all TV’s are manufacture in CHINA.
  
  
  
  
• For transferring this LCD from China to India, company need to make it proper packing like thermocol (Polystyrene) & plastic cover with proper box, etc.
  
  
  
  
  
  
• After they transfer this via different transports to India & then to appropriate city i goes to the following: dealer, then wholesaler or shop and after that delivers at our door.
  
  
  
  
  

Program:

#include < stdio.h >
#include < conio.h >
main()
{
  printf("Hello");
  getch();
}

Output:



Summary:

This article will help fresher candidates to understand execution of C or C++ program with real life example.