1.2.3

• Structured programming

  A popular subsection of procedural programming in which the program flow is given by three main programming structures: Sequence, Selection, Iteration
• Sequence

  Code is executed line-by-line, from top to bottom
• Selection

  A certain block of code is run if a specific condition is met, using IF, ELSE IF and ELSE statements
• Iteration

  A block of code is executed a certain number of times or while a condition is met, using FOR, WHILE or REPEAT UNTIL loops
• Procedural programming is suited to problems that can easily be expressed as a series of instructions using the constructs described above
• Variables

  Named locations in memory where data is stored, the contents of which can be changed while the program is being executed
• Constants


  Named locations in memory, but the value of a constant cannot be edited by the program during execution
• Variables are assigned using the = sign, which is called an assignment operator
• Constants are often capitalised when writing code
• Procedures

  Named blocks of code that perform a specific task, but do not have to return a value
• Functions

  Named blocks of code that perform a specific task and must always return a value
• Relational operators


  Used to make comparisons between two values and produce a result of either True or False, including >, <, =, >=, <=, !=, ==
• Boolean operators

  AND, OR, NOT
• String handling

  Operations that can be performed on strings, including getting the length of a string and getting a substring
• File handling

  Opening a file to read, reading a line from a file, closing a file, opening a file to write, writing a line to a file, checking for end of file
• Assembly language

  The next level up from machine code, part of a family of low-level languages, converted to machine code using an assembler