Library Routines (Cambridge (CIE) O Level Computer Science): Revision Note

Random numbers

RANDOM(1,6)

import random

number = random.randint(1,10)

number = random.randint(-1.0,10.0)

Random choice

import random

choice = random.choice()

// (In pseudocode we just use the RANDOM() function, so no import is needed)

// Ask user to enter a username and password
OUTPUT "Enter a username: "
INPUT User
OUTPUT "Enter a password: "
INPUT Pw

// Check if the user and password are correct
IF User = "admin" AND Pw = "1234" THEN
  // Generate a random 4-digit code
  Code ← ROUND((RANDOM() * 9000) + 1000, 0)
  // Print the code
  OUTPUT "Your code is ", Code
ELSE
  OUTPUT "Invalid username or password."
ENDIF

# importing random library
import random

# asking user to enter a username and password
user = input("Enter a username: ")
pw = input("Enter a password: ")

# checking if the user and password are correct
if user == "admin" and pw == "1234":
    # generating a random 4-digit code
    code = random.randint(1000, 9999)
    
    # printing the code
    print("Your code is", code)
else:
    print("Invalid username or password.")

// Create a list of numbers for the national lottery
DECLARE LotteryNumbers : ARRAY[1:49] OF INTEGER
FOR Index ← 1 TO 49
    LotteryNumbers[Index] ← Index
NEXT Index

// Create an empty list to store the chosen numbers
DECLARE ChosenNumbers : ARRAY[1:6] OF INTEGER

// Loop to pick 6 numbers from the list
FOR Count ← 1 TO 6
    // Use RANDOM to pick a number from the remaining list
    RandomIndex ← ROUND((RANDOM() * (50 - Count)), 0)
    IF RandomIndex = 0 THEN
        RandomIndex ← 1
    ENDIF

    Number ← LotteryNumbers[RandomIndex]

    // Add the chosen number to the list of chosen numbers
    ChosenNumbers[Count] ← Number

    // Remove the chosen number from the list of available numbers
    FOR i ← RandomIndex TO 48
        LotteryNumbers[i] ← LotteryNumbers[i + 1]
    NEXT i
NEXT Count

// Sort the chosen numbers in ascending order
FOR i ← 1 TO 5
    FOR j ← i + 1 TO 6
        IF ChosenNumbers[i] > ChosenNumbers[j] THEN
            Temp ← ChosenNumbers[i]
            ChosenNumbers[i] ← ChosenNumbers[j]
            ChosenNumbers[j] ← Temp
        ENDIF
    NEXT j
NEXT i

// Output the chosen numbers
OUTPUT "The winning numbers are: "
FOR i ← 1 TO 6
    OUTPUT ChosenNumbers[i]
NEXT i

import random

# Create a list of numbers for the national lottery
lottery_numbers = list(range(1, 50))

# Create an empty list to store the chosen numbers
chosen_numbers = []

# Loop to pick 6 numbers from the list
for _ in range(6):
    # Use random.choice to pick a number from the list
    number = random.choice(lottery_numbers)

    # Add the chosen number to the list of chosen numbers
    chosen_numbers.append(number)

    # Remove the chosen number from the list of available numbers
    lottery_numbers.remove(number)

# Sort the chosen numbers in ascending order
chosen_numbers.sort()

# Output the chosen numbers
print("The winning numbers are:", chosen_numbers)

Round

Cost ← 1.9556
OUTPUT ROUND(Cost,2)
# Outputs 1.96

number = 3.14159 rounded_number = round(number, 2)
print(rounded_number)
# Outputs 3.14