C Data Types

Data Types

As explained in the Variables article, a variable in C must be a specified data type, and you must use a format specifier inside the printf() function to display it:

Example

// Create variables
int myNum = 5;             // Integer (whole number)
float myFloatNum = 5.99;   // Floating point number
char myLetter = 'D';       // Character

// Print variables
printf("%d\n", myNum);
printf("%f\n", myFloatNum);
printf("%c\n", myLetter);

Basic Data Types

The data type specifies the size and type of information the variable will store.

In this tutorial, we will focus on the most basic ones:

Data Type Size Description Example
int 2 or 4 bytes Stores whole numbers, without decimals 1
float 4 bytes Stores fractional numbers, containing one or more decimals. Sufficient for storing 6-7 decimal digits 1.99
double 8 bytes Stores fractional numbers, containing one or more decimals. Sufficient for storing 15 decimal digits 1.99
char 1 byte Stores a single character/letter/number, or ASCII values 'A'

Basic Format Specifiers

There are different format specifiers for each data type. Here are some of them:

Format Specifier Data Type Try it
%d or %i int
%f or %F float
%lf double
%c char
%s Used for strings (text), which you will learn more about in a later chapter

Note: It is important that you use the correct format specifier for the specified data type. If not, the program may produce errors or even crash.