How to Use Programming Literals in C

Literals are data used for representing fixed values or constant variables that cannot be changed or modified. They can be used directly in the code. For example:

const int = 10

The 10 represents the value 10, not a variable named 10.

Integers

An integer is known as a numeric literal without a fraction or an exponent. In C programming there are three different types of integer literals:

• Decimal
  • Eg: 0, -10, 22
• Octal (base 8 system)
  • Eg: 021, 077, 033
• Hexadecimal (base 16)
  • Eg: 0x7f, 0x2a, 0x521

Example: change 78 to octal

Divide 78 by 8 until 0

78 ÷ 8 = 9 R 6

9 ÷ 8 = 1 R 1

1 ÷ 8 = 0 R 1

The output will be 116

(Reminder: the remainder from the first division should be in the ones digit)

What the code should look like

void setup(){
    Serial.begin(9600);
    Serial.println(78, OCT);
}
void loop(){

}

Serial Monitor

116

YOU TRY!

In serial.print() enter a number then a comma and OCT. See what the output is in the serial monitor.

Eg: serial.print(78, OCT); should print out 116

Floating-Point Literals

A floating-point literal isa numeric literal that contains a decimal point. It is usually stored in either a decimal form or an exponent form.

Example:

Valid Entries	Invalid Entires
-22.5	123E
0.00034235	3554

Character Literals

• Character literals are used to store a single character within a single quote (‘x’). To store multiple characters, you will use a character array instead.

Valid Entries	Invalid Entries
'a'	'Programming'
'F'	'Flower'
'3'	'integer'
','	'sign'

String Literals

String literals are similar to character literals, the difference is that string literals are capable of storing multiple characters enclosed in double quotation marks (“book”).

Valid Entries	Invalid Entries
"myAge"	'True'
"remainingNumber"	'false'
"percentYield"	'Keys'

What are Literals used for?

Using a literal, you can use the variable name rather than rewriting the value again and again.

Example:

Instead of using 11

void setup(){
    pinMode(11, OUTPUT);
}
void loop(){
    digitalWrite(11, HIGH);
    delay(1000);
    digitalWrite(11, LOW);
    delay(1000);
}

Use a declared integer (Eg. int LED = 11)

int LED = 11; //<---Declare an integer
void setup(){
    pinMode(LED), OUTPUT);
}
void loop(){
    digitalWrite(LED), HIGH);
    delay(1000);
    digitalWrite(LED, LOW);
    delay(1000);
}

Escape Sequences

Some characters/shortcuts that we used cannot be typed in C programming. For example, enter (for a new line), and tab (for indent). Escape sequences are used to replace of these actions.

Escape Sequences	Characters
\f	Form Feed
\n	Newline
\r	Return
\t	Horizontal Tab
\v	Vertical Tab
\	Backslash
\’	Single Quotation mark
\”	Double Quotation mark
?	Question mark
\0	Null Character