Reference.Random History

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December 24, 2009, at 04:04 AM by David A. Mellis -
Changed lines 7-9 from:

long random(max)
long random(min, max)

to:

random(max)
random(min, max)

Changed lines 16-17 from:

long - a random number between min and max - 1

to:

a random number between min and max-1 (long)

Changed lines 52-53 from:
to:
October 13, 2008, at 05:11 PM by David A. Mellis -
Changed line 7 from:

long random(max)

to:

long random(max)\\

October 13, 2008, at 05:10 PM by David A. Mellis -
Changed lines 1-3 from:

long random(max)
long random(min, max)

to:

random()

Added lines 6-9:

Syntax

long random(max) long random(min, max)

Changed lines 11-12 from:

min - lower bound of the random value, inclusive (optional parameter)

to:

min - lower bound of the random value, inclusive (optional)

September 27, 2007, at 06:06 AM by Paul Badger -
Changed lines 16-17 from:

If it is important for sequence of values generated by random() to differ on subsequent executions of a sketch, use randomSeed() to initialize the random number generator with a fairly random input, such as analogRead() on an unconnected pin.

to:

If it is important for a sequence of values generated by random() to differ, on subsequent executions of a sketch, use randomSeed() to initialize the random number generator with a fairly random input, such as analogRead() on an unconnected pin.

September 27, 2007, at 05:53 AM by Paul Badger -
Changed line 29 from:
  // noise will cause the calls to randomSeed() to generate
to:
  // noise will cause the call to randomSeed() to generate
Changed line 31 from:
  // randomSeed() then shuffles the random function
to:
  // randomSeed() will then shuffle the random function.
September 27, 2007, at 05:51 AM by Paul Badger -
September 27, 2007, at 05:50 AM by Paul Badger -
Changed lines 18-19 from:

Conversely, it can occasionally be useful to use pseudo-random sequences that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number.

to:

Conversely, it can occasionally be useful to use pseudo-random sequences that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number, before starting the random sequence.

September 27, 2007, at 05:49 AM by Paul Badger -
Changed lines 8-9 from:

min - lower bound of the random value, inclusive (optional parameter)

to:

min - lower bound of the random value, inclusive (optional parameter)

September 27, 2007, at 05:49 AM by Paul Badger -
Changed lines 8-9 from:

min - lower bound of the random value, inclusive (optional parameter)

to:

min - lower bound of the random value, inclusive (optional parameter)

September 27, 2007, at 05:48 AM by Paul Badger -
Changed lines 8-11 from:

min - lower bound on the random value, inclusive (optional)

max - upper bound on the random number, exclusive

to:

min - lower bound of the random value, inclusive (optional parameter)

max - upper bound of the random value, exclusive

September 27, 2007, at 05:46 AM by Paul Badger -
Changed lines 26-27 from:
  Serial.begin(19200);
to:
  Serial.begin(9600);
Added lines 43-44:
  delay(50);
September 27, 2007, at 05:44 AM by Paul Badger -
Deleted line 39:
Deleted line 42:
September 27, 2007, at 05:44 AM by Paul Badger -
Changed lines 29-30 from:
  // noise will cause the calls to random() to generate
  // different numbers each time the sketch runs.
to:
  // noise will cause the calls to randomSeed() to generate
  // different seed numbers each time the sketch runs.
  // randomSeed() then shuffles the random function
Deleted lines 35-38:
  // print a random number from 10 to 19
  randNumber = random(10, 20);
  Serial.println(randNumber);
Added lines 38-42:
  Serial.println(randNumber);  

  // print a random number from 10 to 19
  randNumber = random(10, 20);
Added line 44:
September 27, 2007, at 05:41 AM by Paul Badger -
Changed lines 18-19 from:

Conversely, it can occasionally be useful to use sequences pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number.

to:

Conversely, it can occasionally be useful to use pseudo-random sequences that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number.

Changed lines 28-29 from:
  // if analog input pin 0 is unconnected, this
  // will cause the calls to random() to generate
to:
  // if analog input pin 0 is unconnected, random analog
  // noise will cause the calls to random() to generate
September 27, 2007, at 05:00 AM by David A. Mellis -
Changed lines 5-6 from:

The random function allows convenient access to pseudo-random numbers for use in sketches.

to:

The random function generates pseudo-random numbers.

Changed lines 8-21 from:

min - optional starting range (ie: from "50" - 300).

max - the largest random number returned (plus one).

In the current version of this function, the max parameter will not be returned, although the minimum will, so for example:

random(10); // returns numbers from 0 to 9

random(-5, 5); // returns numbers from -5 to 4

Consequently, enter a maximum parameter one larger than the maximum integer desired.

min and max are long integers so numbers between -2,147,483,648 and 2,147,483,647 are valid.

to:

min - lower bound on the random value, inclusive (optional)

max - upper bound on the random number, exclusive

Changed lines 13-14 from:

long - the random number.

to:

long - a random number between min and max - 1

Changed lines 16-19 from:

If it is important for a random number sequence to begin on a random number, then call the randomSeed() function using something for a parameter that is fairly random, such as millis(), or analogRead() on a pin with no electrical connection.

Conversely, it can occasionally be useful to use pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed() with the same number as a parameter.

to:

If it is important for sequence of values generated by random() to differ on subsequent executions of a sketch, use randomSeed() to initialize the random number generator with a fairly random input, such as analogRead() on an unconnected pin.

Conversely, it can occasionally be useful to use sequences pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number.

Added lines 27-31:
  // if analog input pin 0 is unconnected, this
  // will cause the calls to random() to generate
  // different numbers each time the sketch runs.
  randomSeed(analogRead(0));
Changed lines 34-42 from:

void loop(){

  randomSeed(analogRead(0));
  // return a random number from 50 - 300
  randNumber = random(50,301);

  // example with only a range, which would return
  // a number between 0 - 300
  // randNumber = random(301);
  Serial.println(r);
to:

void loop() {

  // print a random number from 10 to 19
  randNumber = random(10, 20);
  Serial.println(randNumber);

  // print a random number from 0 to 299
  randNumber = random(300);
  Serial.println(randNumber);
Changed lines 47-48 from:
to:
September 27, 2007, at 04:37 AM by Paul Badger -
Changed lines 10-11 from:

max - the largest random numbers you'd like returned.

to:

max - the largest random number returned (plus one).

Changed lines 18-19 from:

Consequently, enter a maximum parameter one larger than the maximum integer dersired.

to:

Consequently, enter a maximum parameter one larger than the maximum integer desired.

Changed lines 23-24 from:

long - returns the random number.

to:

long - the random number.

Changed lines 26-29 from:

If it is important for a random number series to begin on a random number, then call the randomSeed() function using something for a parameter that is fairly random, such as millis(), or analogRead() on a pin with no electrical connection.

Conversely it can occasionally be useful to use pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed with the same number.

to:

If it is important for a random number sequence to begin on a random number, then call the randomSeed() function using something for a parameter that is fairly random, such as millis(), or analogRead() on a pin with no electrical connection.

Conversely, it can occasionally be useful to use pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed() with the same number as a parameter.

September 27, 2007, at 04:31 AM by Paul Badger -
Changed lines 42-43 from:
  randNumber = random(50,300);
to:
  randNumber = random(50,301);
Changed line 46 from:
  // randNumber = random(300);
to:
  // randNumber = random(301);
September 27, 2007, at 04:31 AM by Paul Badger -
Changed lines 26-27 from:

If it is important for a random number series to begin on a random number, then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

to:

If it is important for a random number series to begin on a random number, then call the randomSeed() function using something for a parameter that is fairly random, such as millis(), or analogRead() on a pin with no electrical connection.

September 27, 2007, at 04:30 AM by Paul Badger -
Changed lines 25-26 from:

Note: If it is important for a random number series to begin on a random number, then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

to:

Note:

If it is important for a random number series to begin on a random number, then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

September 27, 2007, at 04:29 AM by Paul Badger -
Changed lines 25-26 from:

Note: If it is important for a random number series to begin on a random number then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

to:

Note: If it is important for a random number series to begin on a random number, then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

September 27, 2007, at 04:29 AM by Paul Badger -
Changed lines 5-6 from:

The random function allows convenient access to pseudo-random numbers for use in an applications. NOTE: Use this after using the randomSeed() function.

to:

The random function allows convenient access to pseudo-random numbers for use in sketches.

Changed lines 12-13 from:

In the current version of this function, the max parameter will not be returned, although the minimum will so, for example:

to:

In the current version of this function, the max parameter will not be returned, although the minimum will, so for example:

random(10); // returns numbers from 0 to 9

Changed lines 18-19 from:

Consequently enter a maximum parameter one more than the meximum dersired.

to:

Consequently, enter a maximum parameter one larger than the maximum integer dersired.

Added lines 25-28:

Note: If it is important for a random number series to begin on a random number then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

Conversely it can occasionally be useful to use pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed with the same number.

September 27, 2007, at 04:17 AM by Paul Badger -
Changed lines 5-6 from:

The random function allows you to return pseudo-random numbers for use in your applications. NOTE: Use this after using the randomSeed() function.

to:

The random function allows convenient access to pseudo-random numbers for use in an applications. NOTE: Use this after using the randomSeed() function.

Changed lines 10-11 from:

max - the overall range of random numbers you'd like returned.

to:

max - the largest random numbers you'd like returned.

In the current version of this function, the max parameter will not be returned, although the minimum will so, for example:

random(-5, 5); // returns numbers from -5 to 4

Consequently enter a maximum parameter one more than the meximum dersired.

September 27, 2007, at 03:23 AM by Paul Badger -
Added lines 12-13:

min and max are long integers so numbers between -2,147,483,648 and 2,147,483,647 are valid.

May 27, 2007, at 02:33 AM by Paul Badger -
May 27, 2007, at 02:32 AM by Paul Badger -
Deleted lines 39-40:
May 08, 2007, at 07:22 PM by David A. Mellis -
Deleted line 17:

int time;

Changed lines 25-26 from:
  time = millis();
  randomSeed(time);
to:
  randomSeed(analogRead(0));
September 15, 2006, at 06:21 PM by David A. Mellis -
Changed lines 1-3 from:

long random(max)

long random(min, max)

to:

long random(max)
long random(min, max)

September 15, 2006, at 06:21 PM by David A. Mellis -
Changed lines 1-2 from:

long random([min,] max)

to:

long random(max)

long random(min, max)

September 11, 2006, at 05:15 PM by Jeff Gray -
Changed lines 1-2 from:

long random([start,] range)

to:

long random([min,] max)

Changed lines 7-10 from:

start - optional starting range (ie: from "50" - 300).

range - the overall range of random numbers you'd like returned.

to:

min - optional starting range (ie: from "50" - 300).

max - the overall range of random numbers you'd like returned.

September 11, 2006, at 05:05 PM by Jeff Gray -
Added lines 29-32:
  // example with only a range, which would return
  // a number between 0 - 300
  // randNumber = random(300);
September 11, 2006, at 05:04 PM by Jeff Gray -
Added lines 1-38:

long random([start,] range)

Description

The random function allows you to return pseudo-random numbers for use in your applications. NOTE: Use this after using the randomSeed() function.

Parameters

start - optional starting range (ie: from "50" - 300).

range - the overall range of random numbers you'd like returned.

Returns

long - returns the random number.

Example

int time;
long randNumber;

void setup(){
  Serial.begin(19200);
}

void loop(){
  time = millis();
  randomSeed(time);
  // return a random number from 50 - 300
  randNumber = random(50,300);
  Serial.println(r);
}

See also

Reference Home

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