Each variable in C has an associated data type. Each data type requires different amounts of memory and has some specific operations which can be performed over it. Let us briefly describe them one by one:
Following are the examples of some very common data types used in C:
Char : The most basic data type in C. It stores a single character and requires a single byte of memory in almost all compilers.
int : As the name suggests, an int variable is used to store an integer.
Float : It is used to store decimal numbers (numbers with floating point value) with single precision.
Double : It is used to store decimal numbers (numbers with floating point value) with double precision.
Different data types also have different ranges upto which they can store numbers. These ranges may vary from compiler to compiler. Below is list of ranges along with the memory requirement and format specifiers on 32 bit gcc compiler.
Data Type
Memory (bytes)
Range
Format Specifier
Data type : short int
Memory : 2
Range : -32,768 to 32,767
Format specifier : %hd
Data type : unsigned short int
Memory : 2
Range : 0 to 65,535
Format specifier : %hu
Data type : unsigned int
Memory : 4
Range : 0 to 4,294,967,295
Format specifier : %u
Data type : int
Memory : 4
Format specifier : -2,147,483,648 to 2,147,483,647
Format specifier : %d
Data type : long int
Memory : 4
Range : -2,147,483,648 to 2,147,483,647
Format specifier : %ld
Data type : unsigned long int
Memory : 4
Range : 0 to 4,294,967,295
Format specifier : %lu
Data type : long long int
Memory : 8
Range : -(2^63) to (2^63)-1
Format specifier : %lld
Data type : unsigned long long int
Memory : 8
Range : 0 to 18,446,744,073,709,551,615
Format specifier : %llu
Data type : signed char
Memory : 1
Range : -128 to 127
Format specifier : %c
Data type : unsigned char
Memory : 1
Range : 0 to 255
Format specifier : %c
Data type : float
Memory : 4
Format specifier : %f
Data type : double
Memory : 8
Format specifier : %lf
Data type : long double
Memory : 16
Format specifier : %Lf
We can use the sizeof() operator to check the size of a variable. See the following C program for the usage of the various data types:
#include <stdio.h>int main()
{
int a = 1;
char b = 'G';
double c = 3.14;
printf("Hello World!\n");
// printing the variables defined
// above along with their sizes
printf("Hello! I am a character. My value is %c and "
"my size is %lu byte.\n",
b, sizeof(char));
// can use sizeof(b) above as well
printf("Hello! I am an integer. My value is %d and "
"my size is %lu bytes.\n",
a, sizeof(int));
// can use sizeof(a) above as well
printf("Hello! I am a double floating point variable."
" My value is %lf and my size is %lu bytes.\n",
c, sizeof(double));
// can use sizeof(c) above as well
printf("Bye! See you soon. :)\n");
return 0;
}
Output :
Hello World!
Hello! I am a character. My value is G and my size is 1 byte.
Hello! I am an integer. My value is 1 and my size is 4 bytes.
Hello! I am a double floating point variable. My value is 3.140000 and my size i
s 8 bytes.
Bye! See you soon. :)
