C Data Types

In this lesson, you will learn about Data Types in C, their usage, and examples to better understand the topic.

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What are Data Types?

Datatypes represent the variable in C programming, which defines the size and type of the variable. This means how much space a variable requires in-memory storage.

Example

int myFirstVariable;

myFirstVariable is a variable of int (integer) type, and the int size is 4 bytes.

C supports fundamental data types given below in detail. C uses these data types to construct variables.

These are the basic data types: character, integer, float, and void. These basic data types can be classified as signed, unsigned, short, or long.

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int

The integers are the non-decimal data type that includes a number set of {…….., -2, -1, 0, 1, 2, …….}.

Rules for integers are universally the same also in programming languages:

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Basic Syntax

int variable_name;

Example

int mark;

mark is the variable of the integer type

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signed and unsigned

In C programming, signed and unsigned are used as a type modifiers. Data storage can be changed using them.

Example

// Example of integer short long double signed and unsigned
#include <stdio.h>

int main() {
  short intShortVar;
  long intLongVar;
  long long LongLongVar;
  long double LongDoubleVar;
  unsigned int unsignedPosInt = 90;

  int signedPosInt = 90;
  int signedNegInt = -90;

  printf("short size : %d bytes\n", sizeof(intShortVar)); //2 bytes
  printf("long size: %d bytes\n", sizeof(intLongVar)); //8 bytes
  printf("long long size : %d bytes\n", sizeof(LongLongVar)); //8 bytes
  printf("long Double size: %d bytes\n", sizeof(LongLongVar)); //8 bytes
  printf("unsigned int size : %d bytes\n", sizeof(unsignedPosInt)); //4 bytes
  printf("signed positive size: %d bytes\n", sizeof(signedPosInt)); //4 bytes
  printf("signed negative size : %d bytes\n", sizeof(signedNegInt)); //4 bytes
  return 0;
}

Output

short size: 2 bytes
long size: 8 bytes
long long size : 8 bytes
long Double size: 8 bytes
unsigned int size : 4 bytes
signed positive size: 4 bytes
signed negative size : 4 bytes

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char

In C programming, the char type is the fundamental data type used to hold a single character. However, It has the further classification of signed and unsigned. Signed char ranges from 0 to 255, whereas signed char ranges from -128 to 127.

Basic Syntax

char variablename;

Example

// Example of signed and unsigned character
#include <stdio.h>

int main() {
  char myfirstchar = 'q';
  unsigned char unsignedchar = 'p';
  printf("char size:%d byte\n", sizeof(myfirstchar)); //ranges 0 o127 bits
  printf("char size:%d byte\n", sizeof(unsignedchar)); //-127 to 127 bits
  printf("Value of myfirstchar %c\n", myfirstchar);
  printf("value of unsignedchar %c", unsignedchar);
  return 0;
}

Output

char size:1 byte
char size: 1 byte
Value of myfirstchar q
value of unsignedchar p

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Float and Doubles

Doubles and float data types are floating-point numbers and can contain positive and negative (+ and -) sign fractional or decimal numbers. Double variables are 8 bytes, whereas float is 4 bytes in size. This is the only difference between float and double.

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Basic Syntax

float variable_name;
double variable_name;

Example

float marks;
double marks;

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Example of double and float

// Example of double and float
#include <stdio.h>

int main() {
  double PI = 3.14;
  float PII = 3.14;
  printf("double size in %d byte|||||||||||", sizeof(PI));
  printf("PI value is %lf \n", PI);
  printf("float size in %d byte|||||||||||", sizeof(PII));
  printf("PII value is %f \n", PII);
  return 0;
}

Output

double size in 8 byte|||||||||||PI value is 3.140000
float size in 4 byte|||||||||||PII value is 3.140000

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void Types

Void types return no value. Remember, in C; we cannot create variables of void type. If the function is not returning anything, it has a void return type.

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Derived Data Types

C programming language support derived Data Types: Example arrays, unions, pointers, structures.

We will learn about derived types in later chapters.

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Data Types in C, Size, Ranges

Below is a table of Data types in C, their size, and their range.

Data Type	Size	Range
int	2 or 4 bytes	-32,768 to 32,767 or -2,147,483,648 to 2,147,483,647
unsigned int	2 or 4 bytes	0 to 65,535 or 0 to 4,294,967,295
short	2 bytes	-32,768 to 32,767
unsigned short	2 bytes	0 to 65,535
long	8 bytes or 4bytes for 32 bit OS	-9223372036854775808 to 9223372036854775807
unsigned long	8 bytes	0 to 18446744073709551615
char	1 byte	-128 to 127 or 0 to 255
unsigned char	1 byte	0 to 255
signed char	1 byte	-128 to 127

In the next lesson, you will learn about Operators and their usage in the C programming language.