Random Number Generation (OCR GCSE Computer Science): Revision Notes

Random Number Generation

Random number generation is the process of producing unpredictable numbers within a specified range. In programming, this is commonly used for scenarios like games, simulations, or choosing random data from a list.

Key Concepts

• Random numbers are used when you need unpredictability in your programme, like simulating dice rolls or shuffling cards.
• Most programming languages provide built-in functions to generate random numbers.

Creating and Using Random Numbers

To generate random numbers, you typically use a random number function that gives you a number within a specified range. The function may vary depending on the programming language, but it usually works similarly across languages.

Example in Python

In Python, the random module is used to generate random numbers.

Generating a random integer

import random
number = random.randint(1, 10)  
print(number)

This example generates a random integer between 1 and 10.

Generating a random float

number = random.random()
print(number)

This example generates a random float between 0.0 and 1.0

Example in Java

In Java, the Random class is used to generate random numbers.

Generating a random integer

import java.util.Random;
Random rand = new Random();
int number = rand.nextInt(10) + 1; 
System.out.println(number);

This example generates a random integer between 1 and 10.

Example in Pseudocode

A pseudocode representation of random number generation might look like this:

RANDOM_INT = RANDOM(1, 6) q
PRINT RANDOM_INT

This example simulates rolling a dice (number between 1 and 6).

Using Random Numbers in Programmes

Once generated, random numbers can be used in various ways within a programme:

Making Decisions

Use a random number to simulate choices or outcomes.

if random.randint(1, 2) == 1:
    print("Heads")
else:
    print("Tails")

Generating Random Data

Use random numbers to create simulated data or populate a list with random values.

random_numbers = [random.randint(1, 100) for _ in range(5)]  
print(random_numbers)

This example gives a list of 5 random numbers.

Shuffling Data

You can also shuffle items in a list randomly using a random number function.

import random
names = ["Alice", "Bob", "Eve"]
random.shuffle(names)  
print(names)