2.2 - Programming fundamentals

Question 1

What does + do?

Answer 1

Adds two variables

Question 2

What does - do?

Answer 2

Subtracts two variables

Question 3

What does * do?

Answer 3

Multiplies 2 variables

Question 4

What does / do?

Answer 4

Divides 2 variables

Question 5

What does % (MOD) do?

Answer 5

Outputs the remainder of the division

Question 6

What does // (DIV) do?

Answer 6

Divides 2 variables but only shows the integer value (integer division)

Question 7

What does == do?

Answer 7

Shows 2 strings are equal to each other

Question 8

What does != do?

Answer 8

Shows 2 strings are not equal to each other

Question 9

The 3 basic programming constructs

Answer 9

• Selection - the path a program takes when running based on a decision
• Sequence - executing one instruction after the other
• Iteration - the repeated execution of a section of code

Question 10

What is a variable

Answer 10

A named memory location which stores a value that may change during the execution of the program

Question 11

What is a constant

Answer 11

A value that cannot change when the program is run and is assigned when the program is made

Question 12

What is assignment

Answer 12

Giving a variable or constant a value. This is done by an “=” sign

Question 13

What is an identifier and rules that an identifier must follow

Answer 13

• The name of the variable
• It must start with a letter
• Cannot contain special characters
• Cannot have spaces
• NAme should be meaningful

Question 14

Advantages of constants

Answer 14

• Make a program easier to read as they are declared at the start
• Can be changed in one single place instead of changing in multiple places meaning errors are reduced
• Compiler can optimise the code meaning it can be run more quickly when using constants

Question 15

What is a case statement

Answer 15

• Where a program can branch off in several different paths depending on the value of a variable

Question 16

Two forms of iteration and when are they needed

The 3 types of statements fall into these 2 categories

Answer 16

• Count controlled loop (for loop) - when the number of iterations is known ahead of time
• Condition controlled loop (do…until and while loops) - used when the number of iterations is notknown as the variable controlling the iteration changes within the loop itself

Question 17

Difference between a do…until loop and a while loop

Answer 17

• While - Condition is checked AT THE TOP. In a while loop, if the condition is met before the loop, the while loop will never run
• Do…until - the code will execute AT LEAST ONCE as the exit condition is checked AT THE END.

Question 18

What coomand must be used to stop a while loop

Answer 18

• BREAK in python
• ENDWHILE in exam question langauge

Question 19

What is nesting, why is it needed and different types of it

Answer 19

• Including one program construct within another e.g. loop in a loop reducing the amount of code needed making it easier to edit and debug
• Nested selection - increases the number of paths at a decision point
• Nested iteration

Question 20

What is casting and why is it needed

Answer 20

• Changing a data type of a variable from one type to another
• It allows numbers to be manipulated as strings can be