How to Generate Random Numbers and range of numbers in Dart or Flutter Programming with example

This tutorial shows multiple methods for generating random numbers in the Dart programming language.

A random number is a unique value generated within a specified range, ensuring unpredictability for various requests. The generated number always falls within the provided range of values.

#Dart Random Number Generator Example

Dart’s dart:math library includes a Random class for random number generation. It offers the nextInt method, which accepts a maximum value and returns a random number.

int nextInt(int max)

The minimum number is implicitly taken as zero, while the maximum number is the given max value.

Here’s a simple example of generating random numbers:

import 'dart: math';

main() {
  var random = Random();
  print(random.nextInt(10)); //Random number between 0 to 10
  print(random.nextInt(100)); //Random number between 0 to 100
  print(random.nextInt(200)); //Random number between 0 to 100
  print(random.nextInt(1000)); //Random number between 0 to 1000
}

• Import the dart:math package using the import keyword.
• Create a Random variable using the var keyword.
• Call nextInt() with the maximum range.
• Random numbers are always generated between 0 and the provided maximum value.

Output:

4
70
47
294

#Dart Random Number Generator within a Range Example

This example generates random numbers within a specified range between the minimum and maximum values.

import 'dart:math';

main() {
  var random = Random();
  int min = 10;
  int max = 20;
  var randomNumber = min + random.nextInt(max - min);
  print("$randomNumber is random number between $min and $max");
  print(randomNumber);
}

Output:

19 is a random number between 10 and 20
19

#How to Generate a Random Number in Dart Excluding a Particular Number?

For instance, if you wish to generate a random number between 0 and 10, excluding the number 5, you can follow this example.

import 'dart:math';

main() {
  var random = Random();
  var excludeNumber = 5;
  var randomNumber;
  do {
    randomNumber = random.nextInt(10);
  } while (randomNumber == excludeNumber);
  print(randomNumber);
}