Last Updated : 26 Dec, 2023
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Unary operators are the operators that perform operations on a single operand to produce a new value.
Types of unary operators
Types of unary operators are mentioned below:
- Unary minus ( – )
- Increment ( ++ )
- Decrement ( — )
- NOT ( ! )
- Addressof operator ( & )
- sizeof()
1. Unary Minus
The minus operator ( – ) changes the sign of its argument. A positive number becomes negative, and a negative number becomes positive.
int a = 10;
int b = -a; // b = -10
Unary minus is different from the subtraction operator, as subtraction requires two operands.
Below is the implementation of the unary minus (-) operator:
C
#include <stdio.h>
int main()
{
// declaring a positive integer
int positiveInteger = 100;
// using - sign to make the value of positive integers
// to negative
int negativeInteger = -positiveInteger;
printf("Positive Integer = %d\n", positiveInteger);
printf("Negative Integer = %d", negativeInteger);
return 0;
}
Output
Positive Integer = 100Negative Integer = -100
2. Increment
The increment operator ( ++ ) is used to increment the value of the variable by 1. The increment can be done in two ways:
2.1 prefix increment
In this method, the operator precedes the operand (e.g., ++a). The value of the operand will be altered before it is used.
Example:
int a = 1;
int b = ++a; // b = 2
2.2 postfix increment
In this method, the operator follows the operand (e.g., a++). The value operand will be altered after it is used.
Example:
int a = 1;
int b = a++; // b = 1
int c = a; // c = 2
Below is the implementation of the increment ( ++ ):
C
// C program to illustrate increment
#include <stdio.h>
int main()
{
int a = 5;
int b = 5;
printf("Pre-Incrementing a = %d\n", ++a);
printf("Post-Incrementing b = %d", b++);
return 0;
}
3. Decrement
The decrement operator ( — ) is used to decrement the value of the variable by 1. The decrement can be done in two ways:
3.1 prefix decrement
In this method, the operator precedes the operand (e.g., – -a). The value of the operand will be altered before it is used.
Example:
int a = 1;
int b = --a; // b = 0
3.2 postfix decrement
In this method, the operator follows the operand (e.g., a- -). The value of the operand will be altered after it is used.
Example:
int a = 1;
int b = a--; // b = 1
int c = a; // c = 0
Below is the implementation of the decrement ( — ):
C
// C program to illustrate decrement
#include <stdio.h>
int main()
{
int a = 5;
int b = 5;
printf("Pre-Decrementing a = %d\n", --a);
printf("Post-Decrementing b = %d", b--);
return 0;
}
4. NOT ( ! )
The logical NOT operator ( ! ) is used to reverse the logical state of its operand. If a condition is true, then the Logical NOT operator will make it false.
Example:
If x is true, then !x is false
If x is false, then !x is true
Below is the implementation of the NOT (!) operator:
C
// C program to illustrate NOT operator
#include <stdio.h>
int main()
{
int a = 10;
int b = 5;
if (!(a > b))
printf("b is greater than a\n");
else
printf("a is greater than b");
return 0;
}
Output
a is greater than b
5. Addressof operator ( & )
The addressof operator ( & ) gives an address of a variable. It is used to return the memory address of a variable. These addresses returned by the address-of operator are known as pointers because they “point” to the variable in memory.
Example:
& gives an address on variable n
int a;
int *ptr;
ptr = &a; // address of a is copied to the location ptr.
Below is the implementation of the Addressof operator(&):
C
// C program to demonstrate the use of 'address-of(&)'
// operator
#include <stdio.h>
int main()
{
int a = 20;
printf("Address of a = %p", &a);
return 0;
}
Output
Address of a = 0x7fff78c3f37c
6. sizeof()
This operator returns the size of its operand, in bytes. The sizeof() operator always precedes its operand. The operand is an expression, or it may be a cast.
Note: The `sizeof()` operator in C++ is machine dependent. For example, the size of an ‘int’ in C++ may be 4 bytes in a 32-bit machine but it may be 8 bytes in a 64-bit machine.
Below is the implementation of sizeof() operator:
C
// C program to illustrate the sizeof operator
#include <stdio.h>
int main()
{
// printing the size of double and int using sizeof
printf("Size of double: %d\n", sizeof(double));
printf("Size of int: %d\n", sizeof(int));
return 0;
}
Output
Size of double: 8Size of int: 4
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