"Unstructured" Programming

• writing small and simple programs consisting only of one main program.
  
  Here ``main program'' stands for a sequence of commands or statements which modify data which is global throughout the whole program.
  
  
  
• The main program directly operates on global data.
  
  
• disadvantages:
  • program gets quickly too larges
  • no code reusability ( if the same statement sequence is needed at different locations within the program, the sequence must be copied)