Iteration and Repetition (SQA National 5 Computing Science): Revision Note

FOR counter FROM 1 TO 10 DO
    SEND "Hello" TO DISPLAY
END FOR

for counter in range(1, 11):
    print("Hello")

This outputs “Hello” ten times

Python’s range(1, 11) stops before the end value, so it counts 1 to 10

FOR counter FROM 1 TO 10 DO
    IF counter MOD 2 = 0 THEN
        SEND counter TO DISPLAY
    END IF
END FOR

for counter in range(1, 11):
    if counter % 2 == 0:
        print(counter)

This outputs the even numbers between 2 and 10

SET colour TO ""
WHILE colour ≠ "Red" DO
    RECEIVE colour FROM KEYBOARD
END WHILE

colour = ""
while colour != "Red":
    colour = input("Enter colour: ")

This loop continues until the user types “Red”

RECEIVE temperature FROM KEYBOARD
WHILE temperature > 37 DO
    SEND "Patient has a fever" TO DISPLAY
    RECEIVE temperature FROM KEYBOARD
END WHILE

temperature = float(input("Enter temperature: "))
while temperature > 37:
    print("Patient has a fever")
    temperature = float(input("Enter temperature: "))

REPEAT
    RECEIVE colour FROM KEYBOARD
UNTIL colour = "Red"

while True:
    colour = input("Enter colour: ")
    if colour == "Red":
        break

Python has no REPEAT … UNTIL, but you can simulate it using a while True loop and a break statement

SET total TO 0
FOR row FROM 1 TO maxRow DO
    SET rowTotal TO 0
    FOR column FROM 1 TO 10 DO
        SET rowTotal TO rowTotal + Amount[row, column]
    END FOR
    SEND "Total for Row " & row & " is " & rowTotal TO DISPLAY
    SET total TO total + rowTotal
END FOR
SEND "The grand total is " & total TO DISPLAY

for row in range(1, 4):
    for column in range(1, 6):
        print("Row", row, "Column", column)

This will display every combination of row and column values