Unary Operator

What is a Unary Operator?

Unary Operators are the operators which require only one operand. While binary operator requires two operands and tertiary requires three operands.

Unary operators are:

+, -, ++, --, sizeof()

---

1) + and -

 Note: (+) and (-) are not of addition and subtraction but it denotes only sign of operator as positive or negative.

Ex.

+1, +2, +3...

-1, -2, -3...

---

2) ++ and --

It seems to be  ++ (two plus-plus), But it is a single operator.
It is called the increment operator.

Increment operator are of two type:

• i) Pre increment
• ii) Post increment

The meaning of both the increments is the same.

i.e To add +1 in  any value x++ or ++x;
or to increase the value by 1.
x++ is x=x+1

where x is a variable.

Example:
7++ output is 8
25++ output is 26

program: (Pre-increment) 

#include <stdio.h>
#include <conio.h>
int main()
{
    int x=7;
    ++x;  //Where  x++ or ++x increase the value by 1.
    printf("Pre-increment is %d", x);
    getch();
    return 0;
}

Output:

8

Note: Here it is giving output by adding one before 7 (1+7=8).

program: (Post-increment) 

#include <stdio.h>
#include <conio.h>
int main()
{
    int x=7;
    x++;  //increase the value by 1.
    printf("Post-increment is %d", x);
    getch();
    return 0;
}

Output:

8

Note: Here it is giving output by adding 1 after 7 (7+1=8).

---

What is the difference between post-increment and pre-increment?

The operator is written after the variable. The operator is written before the variable.

The priority of the post-increment is the least even more than assignment operators (An exceptional rule). While the priority of pre-increment is the most.

---

3) Decrement Operator

The decrement operator is also the same as an increment operator. But it decreases the value by 1.

Decrement operators are of two types:

i) Pre decrement
ii) Post decrement

The meaning of both the decrements operators is the same.

i.e To substract -1 in  any value x-- or --x;
or to decrease the value by 1.
x-- is x=x-1

where x is a variable.

Example:
7-- output is 6
25-- output is 24

program: (Pre-decrement) 

#include <stdio.h>
#include <conio.h>
int main()
{
    int x=7;
    --x;  //Where  x-- or --x deccrease the value by 1.
    printf("Pre-increment is %d", x);
    getch();
    return 0;
}

Output:

6

Note: Here it is giving output by subtracting one (7-1=6).

program: (Post-decrement) 

#include <stdio.h>
#include <conio.h>
int main()
{
    int x=7;
    x--;  //decrease the value by 1.
    printf("Post-decrement is %d", x);
    getch();
    return 0;
}

Output:

6