C Data Types

Data Types

As explained in the Variables chapter, 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);

Try it Yourself »

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

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`	Try it »
`%f`	`float`	Try it »
`%lf`	`double`	Try it »
`%c`	`char`	Try it »
`%s`	Used for strings (text), which you will learn more about in a later chapter	Try it »

Set Decimal Precision

You have probably already noticed that if you print a floating point number, the output will show many digits after the decimal point:

Example

float myFloatNum = 3.5;
double myDoubleNum = 19.99;

printf("%f\n", myFloatNum); // Outputs 3.500000
printf("%lf", myDoubleNum); // Outputs 19.990000

Try it Yourself »

If you want to remove the extra zeros (set decimal precision), you can use a dot (.) followed by a number that specifies how many digits that should be shown after the decimal point:

Example

float myFloatNum = 3.5;

printf("%f\n", myFloatNum); // Default will show 6 digits after the decimal point
printf("%.1f\n", myFloatNum); // Only show 1 digit
printf("%.2f\n", myFloatNum); // Only show 2 digits
printf("%.4f", myFloatNum); // Only show 4 digits

Try it Yourself »

C Exercises

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C Data Types

Data Types

Example

Basic Data Types

Basic Format Specifiers

Set Decimal Precision

Example

Example

C Exercises

Test Yourself With Exercises

Exercise: