Array as an Abstract Data Type

• What is an array?
  
  • An indexed, homogeneous collection of variables
    
  • Indexed from n-1 where n is the size
    
  • Multi dimensional
    
    • 1 index per dimension
      
  • The upper bound must be greater than or equal to the lower bound
    
• An integer
  
  • is four bytes long, in sequence
    
• to put one thing in to memory is called 'mapping'
  
• row order is where the rows are separated and the columns are adjacent
  
  • column order is the opposite
    
• if you have an array going from [-5 ..+6, +1 … 10, 3…5] of chess pieces
  
  • you would have an array of
    
    • -5, …, +6 of
      
      • An array of 1 , … , 10 of
        
        • An array of 3, …, 5 of chess pieces
          
• Index – lower bound , to find the memory location of an object in a one dimensional array
  
  • For multi dimensional the 2^nd 3^rd… n dimensions start at the end point of the first but find an index the same way as a 1 dimensional array
    
• Array Descriptor
  
  • Dimension count
    
    • For each dimension it needs to lower bound and upper bound and total size
      
    • A prototype array descriptor
      
      •     
        
• A₀ is the hypothetical location in memory where the first lower bound is found in memory.