c++ structured arrays

c++_structured_arrays.md

Structured Arrays (multidimensional arrays)

arrays

• when declared int x[10], you cannot overwrite x with another value
  • array variables are considered constants
• int array[3][2] is an array of size three with integer arrays size two

[
    [int, int],
    [int, int],
    [int, int],
]

• when passed as a parameter, will be function(int **y)

subscript operator

• can work on a pointer expressions
  • x[i] == *(x + i)
• is a binary operator (requires two operands)
  • operand1[operand2]
• the address is computed by the subscript operator and takes into account the size of the elements in the array
  • therefore the index is independent of the actual address of the element
• pointer and array math are interchangeable, since arrays are essentially pointers

sizeof operator

• entirely compile-time
  • replaces all the calls with the given number
• sizeof(array)
• the number of elements can be determined by sizeof(array)/sizeof(array[i])
• since a pointer is a memory address, when doing pointer[1] or pointer + 1 you are actually doing memoryLocation + (1 * sizeof(dataType))
• strictly based on the type
  • even if the type is a pointer to another type, still is pointer type
  • any expression passed in will not be evaluated

memory

• word is the size of a single place of storage / memory in a computer
  • typically 32bit or 64bit
• structs and classes are larger than the primitive data types