Arduino Coding

Data Types

Void

• The void keyword is used only in function declarations.
• It indicates that the function is expected to return no information to the function from which it was called.

Void Loop ( ) {
   // rest of the code
}

Boolean

• Boolean holds one of two values, true or false.
• Each Boolean variable occupies one byte of memory.

boolean val = false;
boolean state = true;

Char

• A data type that takes up one byte of memory that stores a character value.
• Character literals are written in single quotes like: 'A'
• For multiple characters, strings use double quotes: "ABC".
• However, characters are stored as numbers.
• You can see the specific encoding in the ASCII chart.
• This means that it is possible to do arithmetic operations on characters, in which the ASCII value of the character is used.
• For example, 'A' + 1 has the value 66, since the ASCII value of the capital letter A is 65.

Char chr_a = ‘a’;
Char chr_a = 97;

Unsigned char

• Unsigned char is an unsigned data type that occupies one byte of memory.
• The unsigned char data type encodes numbers from 0 to 255.

unsigned char chr_y = 121;

Byte

• A byte stores an 8-bit unsigned number, from 0 to 255.

byte m = 25;

Int

• Integers are the primary data-type for number storage.
• Int stores a 16-bit (2-byte) value.
• This yields a range of -32,768 to 32,767.
• Minimum value of -2^15 and a maximum value of (2^15)-1.
• The int size varies from board to board.

int counter = 32;

Unsigned int

• Unsigned integers are the same as int in the way that they store a 2 byte value.
• Instead of storing negative numbers they only store positive values
• Yielding a useful range of 0 to 65,535 (2^16) - 1).

unsigned int counter = 60;

Word

• A word stores a 16-bit unsigned number.

word w = 1000;

Long

• Long variables are extended size variables for number storage, and store 32 bits (4 bytes).
• From -2,147,483,648 to 2,147,483,647.

long velocity = 102346;

Unsigned long

• Unsigned long variables are extended size variables for number storage and store 32 bits (4 bytes).
• They will not store negative numbers, making their range from 0 to 4,294,967,295 (2^32 - 1).

unsigned long velocity = 101006;

Short

• A short is a 16-bit data-type.
• This yields a range of -32,768 to 32,767 (minimum value of -2^15 and a maximum value of (2^15) - 1).

short val = 13;

Float

• Data type for floating-point number is a number that has a decimal point.
• Floating-point numbers are often used to approximate the analog and continuous values because they have greater resolution than integers.
• Floating-point numbers can be as large as 3.4028235E+38 and as low as -3.4028235E+38.
• They are stored as 32 bits (4 bytes) of information.

float num = 1.352;

Double

• Double precision floating-point number occupies four bytes.

That is, the double implementation is exactly the same as the float, with no gain in precision. On the Arduino Due, doubles have 8-byte (64 bit) precision.

double num = 45.352;

Array

String-char array

String-object

Variables & Constants

This section is under construction.

Operators

This section is under construction.

Control Statements

If Statements

Form 1

if (expression)
   statement;

Form 2

You can use the if statement without braces { } if you have one statement.

if (expression) {
   Block of statements;
}

If Else Statement

if (expression) {
   Block of statements;
}
else {
   Block of statements;
}

If Else-If Else Statements

if (expression_1) {
   Block of statements;
}

else if(expression_2) {
   Block of statements;
}
.
.
.

else {
   Block of statements;
}

Switch Case Statement

switch (variable) { 
   case label:
   // statements
   break;
}

case label: { 
   // statements
   break;
}

default: { 
   // statements
   break;
}

Loops

This section is under construction.

Functions

This section is under construction.

Strings

This section is under construction.

String Objects

This section is under construction.

References

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