Why Do My Random Numbers in Java Seem to Be the Same Every Time?

Understanding Random Numbers Using Seeds in Java

In Java, a seed is used to initialize a Random instance and generate a sequence of pseudorandom numbers. When the same seed is provided, the Random instance produces the same sequence of numbers.

Why Are My Random Numbers the Same Every Time?

In the provided code:

double num = generator.nextDouble() * (0.5);

You are using the same seed for each call to randomGenerator, resulting in the same sequence of random numbers.

How to Fix It

To generate different sequences of random numbers with a seed:

1. Use Different Seeds: Provide a different seed as an argument to the Random constructor each time you call randomGenerator. This will create multiple Random instances, each with a unique seed.
2. Use the Default Seed: If you want to use the same seed across multiple calls, initialize a single Random instance outside of the randomGenerator method with the zero-argument constructor, which uses the current time as the seed.

Example:

private Random generator = new Random(); // outside randomGenerator
double randomGenerator() {
    return generator.nextDouble() * (0.5); // inside randomGenerator
}

Pseudo Random Number Generation

Pseudorandom number generators (PRNGs) generate sequences that appear random but are deterministic and seeded with an initial value. When the same seed is used, the PRNG produces the same sequence.

The above is the detailed content of Why Do My Random Numbers in Java Seem to Be the Same Every Time?. For more information, please follow other related articles on the PHP Chinese website!