Operators

Published Jun 10, 2022

Operators are used to perform operations on variables and values. They are symbols that tell the compiler to perform specific mathematical or logical functions. The C language provides the following types of operators:

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

Arithmetic Operators

C has the following basic arithmetic operators to perform common mathematical operations:

Operator	Name	Description
`+`	Addition	`x + y` returns the sum of `x` and `y`
`-`	Subtraction	`x - y` returns the difference of `x` and `y`
`*`	Multiplication	`x * y` returns the product of `x` and `y`
`/`	Division	`x / y` returns the quotient of `x` and `y`
`%`	Modulo	`x % y` returns the integer remainder of `x` divided by `y`
`++`	Increment	`x++` returns `x + 1`
`--`	Decrement	`x--` returns `x - 1`

int x = 0;
x = x + 4; // x is now 4
x = x - 1; // x is now 3
x = x * 8; // x is now 24
x = x / 4; // x is now 6
x = x % 4; // x is now 2
x++;       // x is now 3
x--;       // x is now 2

Relational Operators

Relational operators compare two values and return true or false.

Operator	Name	Description
`==`	Equal	`x == y` is `true` if `x` and `y` are equal.
`!=`	Not Equal	`x != y` is `true` if `x` and `y` are not equal.
`<`	Less Than	`x < y` is `true` if `x` is less than `y`.
`>`	Greater Than	`x > y` is `true` if `x` is greater than `y`.
`<=`	Less Than or Equal to	`x <= y` is `true` if `x` is less than or equal to `y`.
`>=`	Greater Than or Equal to	`x >= y` is `true` if `x` is greater than or equal to `y`.

int x = 7;
int y = 5;

if (x > y) {
  // This code will run.
}

if (x == y) {
  // This code won't run.
}

Logical Operators

Logical operators operate on boolean values and return boolean values.

Operator	Name	Description
`!`	Not	`!x` is `true` when `x` is `false` and `false` when `x` is `true`.
`&&`	And	`x && y` is `true` only if `x` and `y` are both `true`.
`\|\|`	Or	`x \|\| y` is `true` if either `x` or `y` is `true`.

int x = 7;
int y = 5;

if (x > y \|\| x == y) {
  // This code will run.
}

if (x == y && x < 0) {
  // This code won't run.
}

Bitwise Operators

Bitwise operators manipulate individual bits in an integer.

Operator	Name	Description
`&`	And	Result has bit set only where both operands have that bit set.
`\|`	Or	Result has bit set if either operand has that bit set.
`^`	Xor	Result has bit set only if only one operand has that bit set.
`~`	Not	Takes a single operand and inverts each bit in it.
`<<`	Left shift	`a << b` means `a`‘s bits are shifted to the left `b` spaces.
`>>`	Right shift	`a >> b` means `a`‘s bits are shifted to the right `b` spaces.

int x;

x = 19 & 7;
// x is 3 : 10011 & 00111 = 00011

x = 19 | 7;
// x is 23 : 10011 | 00111 = 10111

x = 19 ^ 7;
x is 20 : 10011 ^ 00111 = 10100

x = 7 << 2;
// x is 28 : 00111 << 2 = 11100

x = 19 >> 2;
// x is 4 : 10011 >> 2 = 00100

Assignment Operators

Assignment operators assign the value on the right to the variable on the left.

Operator	Name	Description
`=`	Assignment	`a = 3` assigns value `3` to variable `a`.
`+=`	Addition Assignment	`a += 3` is short for `a = a + 3`.
`-=`	Subtraction Assignment	`a -= 3` is short for `a = a - 3`.
`*=`	Multiplication Assignment	`a = 3` is short for `a = a 3`.
`/=`	Division Assignment	`a /= 3` is short for `a = a / 3`.
`%=`	Modulo Assignment	`a %= 3` is short for `a = a % 3`.
`&=`	And Assignment	`a &= 3` is short for `a = a & 3`.
`\|=`	Or Assignment	`a \|= 3` is short for `a = a \| 3`.
`^=`	Xor Assignment	`a ^= 3` is short for `a = a ^ 3`.
`<<=`	Left Shift Assignment	`a <<= 3` is short for `a = a << 3`.
`>>=`	Right Shift Assignment	`a >>= 3` is short for `a = a >> 3`.

Misc Operators

Misc operators don’t fit into a particular category.

Operator	Name	Description
`sizeof()`	Addition Assignment	`sizeof(x)` returns the size of variable `x`.
`&`	Address	`&x` returns the address of variable `x`.
`*`	Pointer	`*x` returns a pointer to variable `x`. Not to be confused with multiplication.
`?:`	Conditional Operator	`expression?x:y` returns `x` when `expression` is `true`, `y` otherwise.