Data Types and Structures
When data is stored, it needs to be stored as a specific type of data so it can be used in specific ways. A variable can be declared a constant so it never changes in the code. Some data types are: string, integer, float/real , and Boolean.
Data Type 
Example 
Description 
Typical Memory 
String 
SciGO 123@£$?. 
Any combination of characters, numbers and symbols 
1 Byte/Character 
Integer 
16 
Whole numbers 
2 Bytes 
Float/Real 
16.0 
Decimal Numbers 
4 Bytes 
Boolean 
True 
Boolean or logical data that can only have one of two values 
1 bit/1 Byte 
Character 
! 
Any single ASCII character 
1 Byte 

Strings and Characters

Integers and Floats

Boolean
<
>
Indexing and Length
Each character of a string has an index...

The pseudocode to the left is the same as...

H
i
t
i
t
Here is a table that shows the indexing of the string: example
Note that indexing tends to start from 0
Note that indexing tends to start from 0
Index 
1 
2 
3 
4 
5 
6 
7 
8 

String 
H 
i 
t 
h 
e 
r 
e 
! 
You can also check the length of a string (the number of characters it has). LEN (example) = 9. The length will be an integer.
You can also check the position of the first instance of a character in a string. POS (example, e) = 5. This is also an integer.
Traversal, Concatenation and Slicing
String Traversal  Using a loop to cycle through each character of a string
Example:
Example:
Slicing  extracting part of a string
Example:
SUBSTR (a, b, c) extracts a string from the first index put in (a), to the second (b) to from the string (c) and is used in line 7 above. This function is called substring.
Characters
ASCII  American Standard Code for Information Interchange
ASCII is the most commonly used system for characters in coding.
Each character in ASCII has a (binary) number equivalent. Here is a table of some of the ASCII values:
You can also check the position of the first instance of a character in a string. POS (example, e) = 5. This is also an integer.
Traversal, Concatenation and Slicing
String Traversal  Using a loop to cycle through each character of a string
Example:
 SET example TO "Hi there!"
 FOR i FROM 0 TO LEN (example)  1:
 SEND example [i] TO DISPLAY
 END FOR
Example:
 SET example TO "Sci"
 SEND example + "Go" TO DISPLAY
Slicing  extracting part of a string
Example:
 SET example TO "Computer Science is great!"
 SET word1 TO ""
 FOR i FROM 9 TO 15
 SET word1 TO word1 + example[i]
 END FOR
 SET word2 TO example[9] + example[10] + example[11] + example[12] + example[20] + example[1]
 SEND word2 + " " + SUBSTR (0, 8, example) + word1 TO DISPLAY
SUBSTR (a, b, c) extracts a string from the first index put in (a), to the second (b) to from the string (c) and is used in line 7 above. This function is called substring.
Characters
ASCII  American Standard Code for Information Interchange
ASCII is the most commonly used system for characters in coding.
Each character in ASCII has a (binary) number equivalent. Here is a table of some of the ASCII values:
There are functions to convert between characters and their number equivalent:
ORD ('A') = 65
CHR (65) = 'A'
For lower case letters, add 32 to their upper case value:
ORD ('a') = 97
ASCII means it takes less space to save a number as an integer than as a string
source of image above
ORD ('A') = 65
CHR (65) = 'A'
For lower case letters, add 32 to their upper case value:
ORD ('a') = 97
ASCII means it takes less space to save a number as an integer than as a string
source of image above
Both integers and reals can be used mathematically but integers take less memory and storage space than floats.
The mathematical functions are:
The mathematical functions are:
Operator 
Description 
Example 
+ 
Adds 2 numbers together 
1 + 2 = 3 
 
Subtracts a number from another 
3  2 = 1 
* 
multiplies 2 numbers 
2 * 3 = 6 
/ 
Divides 1 number by another 
6/3 = 2 
DIV (integer division) 
Denotes how many times a number can be divided by a whole number 
11 DIV 2 = 5 
MOD (modulus) 
Gives the remainder of a division 
11 MOD 2 = 1 
^ 
Puts the first number to the power of the second 
2^3 = 8 
The order of operations in computing, as in maths, is: BIDMAS (brackets, indicies, division, multiplication, addition, subtraction)
Boolean Data can only have 1 of 2 values: True or False. This is represented as 1 (True) or 0 (False). Selection is an example of where Boolean logic is used to see whether or not a condition is the case.

The pseudocode to the left is an example. If the number 16 is the input, the condition on line 2 is True but the condition on line 3 is False so nothing is displayed.
The IF statement on line 3 is within another so it is called a nested IF statement. The same naming rule applies to functions and other aspects of computer science. In this case, the lines 2 and 3 can be condensed into: 2. IF number > 0 AND number < 10: 
AND is a Boolean operator as well as OR, NOT and XOR.
The output of each for different inputs can be shown in Truth Tables. In other words, we can make a table that tells us the result/outcome when we put something into each operator. Here are the truth tables for each, the output is on the right of the vertical line.
link to source
The output of each for different inputs can be shown in Truth Tables. In other words, we can make a table that tells us the result/outcome when we put something into each operator. Here are the truth tables for each, the output is on the right of the vertical line.
link to source
NOT  For a True output, the input must be False. NOT takes in one input then switches it:
Each of these have their own symbol for when we draw logic gates (an idealised or physical device that carries out a Boolean operation):
 P = NOT A
 P = A AND B
 P = A OR B
 P = A XOR B
Each of these have their own symbol for when we draw logic gates (an idealised or physical device that carries out a Boolean operation):
A similar case to XOR is NAND (NOT(AND)) which is a commonly used logic gate so, though admittedly not as complicated as XOR has its own logic gate symbol.