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Cover image for Understand chars in 5 mins or less
Dave Mcsavvy
Dave Mcsavvy

Posted on

Understand chars in 5 mins or less

What is the char type in C and how should it be used.

Before we dive into these, let's have a quick glance at C types.

Types In C

Types are useful to us because they allow us to handle values in a specific way.
In the backend though, C uses types to determine how much memory to allocate for a given value.
C is very particular about memory and it needs to know the type of every value.

The Char type

This special type refers to printable and control character - basically every key on your keyboard!

Declaring Characters

The syntax for declaring a variable as a char looks like this

char character = 'Z';
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Note that single quotes '' are used instead of double quotes ""

Under the hood, all char type translate to an integer. So you declare character like this

char c = 48
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Or

char c = '0'
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You can view the a table of all characters and their integer representation here


Char Operations

C provides a library for handling characters in an exciting way πŸ”₯
You can use that library by including the ctype.h library at the top of your script like this

#include <ctype.h>
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Here are a few utilities the library gives you for free...

check is a character is lower case

char c = 'a';

if (islower(c))
    // do something 
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islower returns 1 if a character is lower case, and 0 if it's not.

check is a character is upper case

char c = 'A';

if (isupper(c))
    // do something 
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isupper returns 1 if a character is upper case, and 0 if it's not.

check is a character is an alphabet

char c = 'A';

if (isalpha(c))
    // do something 
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isalpha returns 1 if a character is an alphabet, and 0 if it's not.

check is a character is a digit

char c = '4';

if (isdigit(c))
    // do something 
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isdigit returns 1 if a character is a decimal number, and 0 if it's not.

check is a character is a digit or alphabet

char c = 'y';

if (isalphanum(c))
    // do something 
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isalphanum returns 1 if a character is a digit or alphabet, and 0 if it's not.

Bet you can guess what these functions do

  • ispunc

  • isspace

You can also convert characters to uppercase and lowercase using toupper and tolower respectively.

char c = 'A';

// Switch case
if (isupper(c))
    c = tolower(c);
else if (islower(c))
    c = toupper(c));
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Spoilers
Emojis are also chars!

char damn = 'πŸ₯΅'
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