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Prints data to the serial port as human-readable ASCII text followed by a carriage return character (ASCII 13, or '\r') and a newline character (ASCII 10, or '\n'). This command takes the same forms as Serial.print().


Serial.println(val, format)


Serial: serial port object. See the list of available serial ports for each board on the Serial main page.
val: the value to print. Allowed data types: any data type.
format: specifies the number base (for integral data types) or number of decimal places (for floating point types).


println() returns the number of bytes written, though reading that number is optional. Data type: size_t.

Example Code

 Analog input reads an analog input on analog in 0, prints the value out.
 created 24 March 2006
 by Tom Igoe

int analogValue = 0;    // variable to hold the analog value

void setup() {
  // open the serial port at 9600 bps:

void loop() {
  // read the analog input on pin 0:
  analogValue = analogRead(0);

  // print it out in many formats:
  Serial.println(analogValue);       // print as an ASCII-encoded decimal
  Serial.println(analogValue, DEC);  // print as an ASCII-encoded decimal
  Serial.println(analogValue, HEX);  // print as an ASCII-encoded hexadecimal
  Serial.println(analogValue, OCT);  // print as an ASCII-encoded octal
  Serial.println(analogValue, BIN);  // print as an ASCII-encoded binary

  // delay 10 milliseconds before the next reading:

Notes and Warnings

For information on the asyncronicity of Serial.println(), see the Notes and Warnings section of the Serial.write() reference page.