Scratch Programming Notes PDF

Scratch Programming with pen extension Student notes Command A command is a single instruction. It is sometimes referred to as a statement. Algorithm A sequence of commands to achieve a particular outcome. e.g. an algorithm could be a set of commands to draw a zigzag line Prog...

Scratch Programming with pen extension Student notes Command A command is a single instruction. It is sometimes referred to as a statement. Algorithm A sequence of commands to achieve a particular outcome. e.g. an algorithm could be a set of commands to draw a zigzag line Programming concept - sequence The order in which commands are executed. e.g. the same range of commands in a different order can produce different outcomes. Programming concept - iteration Iteration relates to the repetition of commands/sets of commands. There are different types of looping structures, for example in Scratch there is a FOREVER loop and a REPEAT loop Subroutines (a procedure is a type of subroutine) Subroutines are predefined sets of commands that can be called / invoked by using the name of them in the script. The images below show the subroutine, triangle, and how it is used: Variable A named placeholder for data. It can store different types of data and the value of the data can be changed. In programming two impotant types of variable are: Global variables – these exist outside a procedure and can be used by different procedures Local variables – these are used within a particular procedure Thinking about global and local variables, in Scratch, a variable can be made for a single sprite, or all sprites. Programming concept - selection Selection is where conditions are used to determine when commands should be executed. An IF ELSE statement is an example of selection.