1 - Programming GapFill

There are four programming constructs, which determine the order and quantity in which instruction executes. Computation Incrementation Selection Sequence involves each instruction executing once, in a fixed order.  Iteration Selection Incrementation Sequence , indicated by keywords such as ’if’ ’until’ ’public’ ’do’ and ’protected’ ’begin’ ’loop’ ’case’ , involves one path being taken through the code where more than one path was available.  Recursion Sequence Selection Iteration is the repeated execution of a block of code, which is signified by programming keyworks such as ’private’ ’while’ ’end’ ’if’ and ’catch’ ’case’ ’for’ ’default’ .  Finally, computation recursion selection iteration is the construct in which a subroutine calls itself.

When a subroutine calls another subroutine, or calls itself, data can be passed to the called subroutine by way of global variables parameters fields member variables .  There are two ways of doing this.  Passing by literal variable value field involves making a copy of the data that's passed in.  Passing by index value reference literal involves passing a pointer to the called subroutine – any changes made to this data entail changes being made to the original, as there is no copy.  A subroutine might return a value, in which case it is referred to as a function formula procedure pass .  If it returns no value, it is known as a call procedure pass method .