Print Versus Println

Part of the First Circuits section of Coddy's Arduino journey. Lesson 8 of 22.

Serial.println() prints its text and then starts a new line. Serial.print() prints the text and stays on the same line, so whatever comes next is added right after it.

Serial.print("Speed: ");
Serial.println("fast");
Serial.println("Done");

The monitor shows two lines:

Speed: fast
Done

Build a line from several pieces with print(), and finish it with println(). The space inside "Speed: " keeps the words apart: without it the monitor shows Speed:fast.

Printing what the sketch is doing, as it does it, is the main way to find out why a sketch does not work.

Challenge

Easy

Blink the LED on pin 13 (500 ms on, 500 ms off) and report each change in the Serial monitor:

when you turn it on, print LED: on
when you turn it off, print LED: off
print "LED: " with print(), then the word with println(), so each status is one line

Press Run, then Check.

Try it yourself

void setup() {
  pinMode(13, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // print LED: on
  digitalWrite(13, HIGH);
  delay(500);
  // print LED: off
  digitalWrite(13, LOW);
  delay(500);
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in First Circuits

1Hello, Board

Blink an LED Setup and Loop Change the Blink Speed An LED of Your Own Two LEDs Taking Turns Comments in Your Sketch

4Decisions

Decisions with if Choosing with if and else Comparing Values Combining Conditions Read a Button

2Talking to Your Computer

Hello, Serial MonitorPrint Versus PrintlnPrinting Numbers Your First Variable Counting Up When an Int Runs Out

3Math on the Board

Named Constants Arithmetic Operators Integer Division Decimals with float A Blink That Speeds Up

Practice on your own: Arduino playground