Constants and Operators in C

Constants

A constant is a fixed value that does not change during the execution of a program.

Types of Constants

1. Integer Constants

Whole numbers without a decimal point.

Examples:

10
-25
1000

2. Floating-Point Constants

Numbers containing a decimal point.

Examples:

3.14
25.75
-0.5

3. Character Constants

A single character enclosed in single quotes.

Examples:

'A'
'Z'
'5'

4. String Constants

A sequence of characters enclosed in double quotes.

Examples:

"Hello"
"C Programming"

5. Symbolic Constants

Defined using the #define preprocessor directive.

Syntax:

#define CONSTANT_NAME value

Example:

#define PI 3.14159
#define MAX 100

6. Constant Variables

Declared using the const keyword.

Example:

const int DAYS = 7;

Operators in C

An operator is a symbol used to perform operations on variables and constants.

1. Arithmetic Operators

Operator	Meaning	Example
`+`	Addition	`a + b`
`-`	Subtraction	`a - b`
`*`	Multiplication	`a * b`
`/`	Division	`a / b`
`%`	Modulus (Remainder)	`a % b`

Example:

int a = 10, b = 3;

printf("%d\n", a + b);
printf("%d\n", a % b);

2. Relational Operators

Operator	Meaning
`==`	Equal to
`!=`	Not equal to
`>`	Greater than
`<`	Less than
`>=`	Greater than or equal to
`<=`	Less than or equal to

Example:

if (a > b)
{
    printf("a is greater");
}

3. Logical Operators

Operator	Meaning
`&&`	Logical AND
`
`!`	Logical NOT

Example:

if (age >= 18 &amp;&amp; age &lt;= 60)
{
    printf("Eligible");
}

4. Assignment Operators

Operator	Example	Meaning
`=`	`a = 5`	Assign
`+=`	`a += 2`	Add and assign
`-=`	`a -= 2`	Subtract and assign
`*=`	`a *= 2`	Multiply and assign
`/=`	`a /= 2`	Divide and assign
`%=`	`a %= 2`	Modulus and assign

5. Increment and Decrement Operators

Operator	Meaning
`++`	Increment by 1
`--`	Decrement by 1

Example:

int x = 5;

x++;
x--;

6. Bitwise Operators

Operator	Meaning
`&`	Bitwise AND
`	`
`^`	Bitwise XOR
`~`	Bitwise NOT
`<<`	Left Shift
`>>`	Right Shift

7. Conditional (Ternary) Operator

Syntax:

condition ? expression1 : expression2;

Example:

int max = (a > b) ? a : b;

8. sizeof Operator

Returns the size (in bytes) of a data type or variable.

Example:

printf("%zu", sizeof(int));

Example Program

#include &lt;stdio.h>

#define PI 3.14159

int main()
{
    const int DAYS = 7;

    int a = 10, b = 5;

    printf("Addition = %d\n", a + b);
    printf("Subtraction = %d\n", a - b);
    printf("Multiplication = %d\n", a * b);
    printf("Division = %d\n", a / b);
    printf("Remainder = %d\n", a % b);

    if (a > b)
        printf("a is greater than b\n");

    printf("PI = %.2f\n", PI);
    printf("Days = %d\n", DAYS);

    return 0;
}

Output

Addition = 15
Subtraction = 5
Multiplication = 50
Division = 2
Remainder = 0
a is greater than b
PI = 3.14
Days = 7

Summary

Constants are fixed values that cannot be changed during program execution.
Common types of constants are integer, floating-point, character, string, symbolic (#define), and const variables.
Operators perform operations on variables and constants.
The major categories of operators in C are:
- Arithmetic Operators
- Relational Operators
- Logical Operators
- Assignment Operators
- Increment/Decrement Operators
- Bitwise Operators
- Conditional (Ternary) Operator
- sizeof Operator