Relational Operators in C

The following table shows all the relational operators supported by C language. Assume variable A holds 10 and variable B holds 20 then −

Operator	Description	Example
==	Checks if the values of two operands are equal or not. If yes, then the condition becomes true.	(A == B) is not true.
!=	Checks if the values of two operands are equal or not. If the values are not equal, then the condition becomes true.	(A != B) is true.
>	Checks if the value of left operand is greater than the value of right operand. If yes, then the condition becomes true.	(A > B) is not true.
<	Checks if the value of left operand is less than the value of right operand. If yes, then the condition becomes true.	(A < B) is true.
>=	Checks if the value of left operand is greater than or equal to the value of right operand. If yes, then the condition becomes true.	(A >= B) is not true.
<=	Checks if the value of left operand is less than or equal to the value of right operand. If yes, then the condition becomes true.	(A <= B) is true.

Example

Try the following example to understand all the relational operators available in C −

#include <stdio.h>

main() {

   int a = 21;
   int b = 10;
   int c ;

   if( a == b ) {
      printf("Line 1 - a is equal to b\n" );
   } else {
      printf("Line 1 - a is not equal to b\n" );
   }
 
   if ( a < b ) {
      printf("Line 2 - a is less than b\n" );
   } else {
      printf("Line 2 - a is not less than b\n" );
   }
 
   if ( a > b ) {
      printf("Line 3 - a is greater than b\n" );
   } else {
      printf("Line 3 - a is not greater than b\n" );
   }
   
   /* Lets change value of a and b */
   a = 5;
   b = 20;
 
   if ( a <= b ) {
      printf("Line 4 - a is either less than or equal to  b\n" );
   }
 
   if ( b >= a ) {
      printf("Line 5 - b is either greater than  or equal to b\n" );
   }
}

When you compile and execute the above program, it produces the following result −

Line 1 - a is not equal to b
Line 2 - a is not less than b
Line 3 - a is greater than b
Line 4 - a is either less than or equal to  b
Line 5 - b is either greater than  or equal to b

Arithmetic Operators in c

C - Operators

An operator is a symbol that tells the compiler to perform specific mathematical or logical functions. C language is rich in built-in operators and provides the following types of operators −

• Arithmetic Operators
• Relational Operators
• Logical Operators
• Bitwise Operators
• Assignment Operators
• Misc Operators

Arithmetic Operators in C

The following table shows all the arithmetic operators supported by the C language. Assume variable A holds 10 and variable B holds 20, then −

Operator	Description	Example
+	Adds two operands.	A + B = 30
−	Subtracts second operand from the first.	A − B = -10
*	Multiplies both operands.	A * B = 200
/	Divides numerator by de-numerator.	B / A = 2
%	Modulus Operator and remainder of after an integer division.	B % A = 0
++	Increment operator increases the integer value by one.	A++ = 11
--	Decrement operator decreases the integer value by one.	A-- = 9

Example

Try the following example to understand all the arithmetic operators available in C −

#include <stdio.h>

main() {

   int a = 21;
   int b = 10;
   int c ;

   c = a + b;
   printf("Line 1 - Value of c is %d\n", c );
 
   c = a - b;
   printf("Line 2 - Value of c is %d\n", c );
 
   c = a * b;
   printf("Line 3 - Value of c is %d\n", c );
 
   c = a / b;
   printf("Line 4 - Value of c is %d\n", c );
 
   c = a % b;
   printf("Line 5 - Value of c is %d\n", c );
 
   c = a++; 
   printf("Line 6 - Value of c is %d\n", c );
 
   c = a--; 
   printf("Line 7 - Value of c is %d\n", c );
}

When you compile and execute the above program, it produces the following result −

Line 1 - Value of c is 31
Line 2 - Value of c is 11
Line 3 - Value of c is 210
Line 4 - Value of c is 2
Line 5 - Value of c is 1
Line 6 - Value of c is 21
Line 7 - Value of c is 22

Data Types in C

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.

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
long int	8	-2,147,483,648 to 2,147,483,647	%ld
unsigned long int	8	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		%f
double	8		%lf
long double	16		%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. :)