Basic Library
Digital I/O
Analog I/O
Advanced I/O
Time
Math
Trigonometry
Random Numbers
Bits and Bytes
Interrupts
Serial Comm.
Standard Library
Ethernet
Ethernet (Server)
Ethernet (Client)
Servo Motor
Stepping Motor
Character LCD
EEPROM
SPI
I2C (Wire)
SD
SD (File Operations)
Image Processing
Periodic Operation
Clock (RTC)
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
- Obtains random numbers. Always call the randomSeed function before using this function.
- 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, exclusive (optional) - Returns
- A random number (long)
Sample Program
Output random numbers between 0 and 99 in 100ms intervals via serial communications.
#include <Arduino.h>
#define INTERVAL 100
void setup()
{
Serial.begin(9600);
randomSeed(millis());
}
void loop()
{
Serial.println( random(0, 100) );
delay(INTERVAL);
}