Basic Library
Digital I/O
Analog I/O
Advanced I/O
Time
Math
Trigonometry
Random Numbers
Bits and Bytes
Interrupts
Communication
Standard Library
Servo Motor
Stepper
Liquid Crystal
EEPROM
SPI
I2C (Wire)
SD Card
SD Card (File Control)
Ethernet
Ethernet (Server)
Ethernet (Client)
Firmata
Periodic Operation
Power Save
Clock (RTC)
SoftwareSerial
Utility
Random Number
This library allows users to get a random number.
randomSeed
Description
randomSeed() initializes the pseudo-random number generator, causing it to start at an arbitrary point in its random sequence. This sequence, while very long, and random, is always the same.
Syntax
randomSeed(unsigned int seed)
Parameters
seed: A number to generate the seed
Returns
None
random
Description
The random function generates pseudo-random numbers.
Syntax
long random(long min_num, long max_num)
Parameters
min_num: Lower bound of the random value, inclusive (optional)
max_num: Upper bound of the random value, exclusiveReturns
A random number between min and max-1 (long)
Example
This example outputs a random number from 0 to 99 every 100ms.
#include <Arduino.h>
#define INTERVAL 100
void setup()
{
Serial.begin(9600);
randomSeed(millis());
}
void loop()
{
Serial.println( random(0, 100) );
delay(INTERVAL);
}