Skip to main content

Data Types and Qualifiers in C

There are four data types in C language. They are,
Data Types
  Basic data types   int, char, float, double
  Enumeration data type   enum
  Derived data type   pointer, array, structure, union
  Void data type   void

Here we will discuss only basic data types.

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 primitive 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.
void:value less

Qualifiers are used to qualify the data type.The following are the qualifiers used with primitive data type.
unsigned, signed(default)

The unsigned qualifier avoids sign bit.
The qualifier const can be applied to the declaration of any variable to specify that its value will not be changed directly.
Value of any variable can be changed either by program or external device.

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
short int                   2       -32,768 to 32,767                   %hd                   
unsigned short int          2       0 to 65,535                         %hu
unsigned int                4       0 to  4,294,967,295                 %u
int                         4      -2,147,483,648 to 2,147,483,647      %d or %i
long int                    4      -2,147,483,648 to 2,147,483,647      %ld
unsigned long int           4       0 to 4,294,967,295                  %lu
long long int               8       -(2^63) to (2^63)-1                 %lld
unsigned long long int      8       0 to 18,446,744,073,709,551,615     %llu
signed char                 1       -128 to 127                         %c 
unsigned char               1       0 to 255                            %c
float                       4       3.4E-38  to 3.4E+38                 %f
double                      8       1.7E-308 to 1.7E-30                 %lf
long double                12      3.4E-4932 to 1.1E+4932               %Lf
Data type size (in byte)
char 1
Short int 2
int 2
long int or long 4
float 4 (6 decimal places of precision)
double 8 (15
decimal places of precision) 
long double 10 (19 decimal places of precision)

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;
//printing the variables defined above along with their sizes
printf("character. value is %c and size is %lu byte.\n",b,sizeof(char));
printf(" integer. value is %d and  size is %lu  bytes.\n", a,sizeof(int));
printf(" double value is %lf and  size is %lu ytes.\n",c,sizeof(double));
return 0;
 The header file limits.h defines limits of integer types and the user can use the constants defined in it.
#include <limits.h>
#include <stdio.h>
int main()
printf("The max value of integer=%d",INT_MAX);
printf("The min value of integer=%d",INT_MIN);
return 0;
} The header file float.h defines macros that allow you to use these values and other details about the binary representation of real numbers in your programs. The following example prints the storage space taken by a float type and its range values −

#include <stdio.h>
#include <float.h>
int main() {
   printf("Storage size for float : %d \n", sizeof(float));
   printf("Minimum float positive value: %E\n", FLT_MIN );
   printf("Maximum float positive value: %E\n", FLT_MAX );
   printf("Precision value: %d\n", FLT_DIG );
   return 0;


Popular posts from this blog

KTU C programming question paper and evaluation scheme

PART A 1 An identifier is a sequence of characters invented by the programmer or to identify or name a specific object. The sequence of characters may be letters, digits, and special character ‘_’known as an underscore Rules: i)Identifiers should start with alphabets. ii)Identifiers are case sensitive iii)A numeric digit should not be the first character iv)Identifier name should not be a keyword v)Identifier may be of any reasonable length 1mark

2mark 2 Associativity defines the direction, left to right or right to left in which operator act upon its operands Unary operators have associativity is from right to left. For examplein the expression &--x, pre decrement works first and then address of operator works Direction + example<

Files in C

A file is a repository of data that is stored in a permanent storage media, mainly in secondary memory. In order to use the files we should learn how to read information from a file and how to write information into a file. A very important concept in C is the stream.The stream is a common logical interface to the various devices( files).A stream is linked to a file while using an open operation. A stream is disassociated from a file while using a close operation. The current location, also referred to as the current position, is the location in a file where the next fie access will occur.There are two types of streams text and binary. The following are some difference between text and binary files ·Text file is human readable because everything is stored in terms of text. In binary file everything is written in terms of 0 and 1, therefore binary file is not human readable. ·A newline(\n) character is converted into the carriage return-linefeed combination before being written to the d…

Linear and Binary Search in C

Searching is one of the most common problems that arise in computing. Searching is the algorithmic process of finding a particular item in a collection of items. A search typically answers either True or False as to whether the item is present. On occasion it may be modified to return where the item is found. Search operations are usually carried out on a key field. Consider searching for a given value k in an array A of size n. There are 2 basic approaches: sequential search and binary search.
Linear (Sequential) Search When data items are stored in a collection such as a list or array , we say that they have a linear or sequential relationship. Each data item is stored in a position relative to the others. In C array, these relative positions are the index values of the individual items. Since these index values are ordered, it is possible for us to visit them in sequence. This process gives rise to our first searching technique, the sequential search. Starting at the first item in …