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Lesson 56 : What is a function? | Arduino Step By Step Course

Part 6: Arduino Practiall Programming

In this lesson we learn how what a function is and how to define it. We learn about return type, about arguments and parameters.

  • 00:00 what is a function?
  • 02:01 Example 1 : Void
  • 03:48 Example 2: Integer
  • 07:13 Example 3: float
  • 08:05 Example 4: Void (no return, no argument)
  • 08:50 Example 5: String
  • 09:34 Example 6: a little complex
  • 10:20 Code examples demo
  • 17:32 Decimal point issue

  * S06-01 
  Lesson 56 : What is a function? | Arduino Step By Step Course
 * This is Arduino sketch to demonstrate "functions" in Arduino
 Please watch video for full details:
 * Written by Ahmad Shamshiri for and Robojax YouTube channel
 * on Jan 03, 2019 at 15:25 in Ajax, Ontario, Canada

 * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.* 
 * This code has been download from
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <>.

const float voltage = 3.3;

void setup() {
   // Robojax Arduino floating points
  Serial.begin(9600);// initialize the Serial Monitor

void loop() {
  Serial.println(    pi(), 10  );


  printText: prints the text on Serial monitor
  @param t is String text
  @ returns nothing
void printText(String t)


 * getDays is calculation the number of days in a year
 * @param a is integer 
 * @param returns integer value of number of days
int getDays(int a)
  return (a * 365);// multiply  a by 365 to get number of days and return it

float getArea(float l, float w)
  float area = l * w;
  return area;

String makeText(double temperature)
  String newText;
   if (temperature > 60.5)
    newText = "Very hot";
    newText = "Not hot";
   return newText;

double pi()

  double p = 3.141592;// 6 decimal points
  return p;// returns value of pi

float getPower(float i)
  return i*voltage;// 


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