How to generate random number in dart program and also Generating a random number within a range in dart code

 

In this dart tutorial (article), we will learn how to generate random number in dart.

In Dart programming, A Random number are often used in flutter application where a user can generate a unique key number.

What is Random Number in dart program?

In dart, A Random Number is a randomly generated from a large set of numbers & select a number using some mathematical algorithm.

Generating random number are commonly implemented in many flutter application having a feature like OTP verification for user SignIn.

Dart Random class – In math package

In dart, we have a class named “Random” which is used to generate random integer number, bool , random decimal number.

Note: To use Random class in dart, we must import ‘dart:math’ package because Random Class is defined in dart:math package.

It can generate random booleon, integer and double value by using its method provided.

Method on Math.random class

Method	Description
nextBool() =>	Generate either true or false randomly.
nextDouble() =>	Generate an positive floating point number ranging from 0.0 to 1.0.
nextInt(int max) =>	Generate a positive number range from 0 to max (as defined) Eg: random.nextInt(6); // Here 6 is a range,  number will generate from 0 – 6.

Dart Porgram to generate random number bool, int, double

1. Dart Program to generate  random number

import 'dart:math';
import 'package:flutter/material.dart';

void main(){
  //instantinate random class from dart:math packages
   Random randomclass= Random();
   //below code Random number betwen 0-50
   print(randomclass.nextInt(50));
   //below code Randomly generate true or false 
   print(randomclass.nextBool());
   //below code random double betwen 0.0-1.0
   print(randomclass.nextDouble());

}

In this example, we are going to show you the simple way to generate random intiger numbers , double values , within the minimum and maximum range. See the example below for more details.

Import dart:math:

import 'dart:math';

Generate Random Integer with Dart:

int random = Random().nextInt(1000); //1000 is MAX value
//generate random number below 1000

Here is the full code  Snipet to generate a intiger number form 0-100

import 'dart:math';

import 'package:flutter/material.dart';
void main(){
  //generating Random Intiger
  Random randomclass=Random();
  int generatedNumber= randomclass.nextInt(100); //generate betwen 0-100
}

Generate Random Double Value:

       double randomdouble = Random().nextDouble();
       //generate random double within 0.00 - 1.00;

    randomdouble = double.parse(randomdouble.toStringAsFixed(4));
//toStringAsFixed will fix decimal length to 4, 0.3454534 = 0.3454

double.parse(randomdouble.toStringAsFixed(4))//generates 4 digit only after decimal point

here is the full code snipet to generate Random double value from 0.00 to 1.00

import 'dart:math';
import 'package:flutter/material.dart';
void main(){
  //generating Random Intiger
  Random randomclass=Random();
  //generate double number from 0.00 to 1.00
  double randomdouble= randomclass.nextDouble();
  //to display only specific digit after a decimal point use the
  //following code
  double only4digit= double.parse(randomdouble.toStringAsFixed(4));
  print(only4digit);
  //only 4 digit is dispalyed after decimal point

}

Generate Random Integer within Min and Max range:

int randomminmax = min + Random().nextInt(max - min);
//generate random number within minimum and maximum value

Here is the full code Snipet to generate Number betwen min - max value

import 'dart:math';

import 'package:flutter/material.dart';
void main(){
  Random randomclass= Random();
  //generates number betwen 50-100
  int BetwenMinAndMax= 50+ randomclass.nextInt(100-50);
  print(BetwenMinAndMax);

}