2.2 Problem Solving and Programming

Sequence

Code is executed line by line from top to bottom

Branching (selection)

A block of code is run if a condition is met (IF statements)

Iteration

A block of code is repeatedly ran for a certain number of times or until a condition is met (FOR/WHILE loops)

Recursion

When a function calls itself during its execution until a stopping condition is met

Advantages of recursion

• Less lines of code = less likely to have errors

• Good for divide and conquer problems

Disadvantages of recursion

• Uses more memory than iteration

• If not a stopping condition stack overflows may occur

• Harder to understand for developers

Advantages of iteration

• More efficient in time and memory than recursion

• No risk of stack overflows

• Easier to understand for developers

Disadvantages of iteration

• Some algorithms are harder to write iteratively (divide and conquer and tree traversal)

• Code can come overly complex for longer algorithms

Local variable

Variable that is declared in a function/procedure and can only be accessed in that function

Global variable

Variable that is declared outside any function and can be accessed anywhere in the program

Benefits of using procedures and functions

• Less memory used

• Can be reused multiple times

• Makes programming more manageable splitting it into sections

Difference between function and procedure

A function returns a value whereas a procedure doesn’t

How are parameters used into a subroutine

1. Passed by value - treated like a local variable and discarded at the end

2. Passed by reference - address of the parameter is given, the value can be updated

IDE

Integrated development environment - software that allows programmers to write, test and debug code