Increment And Decrement Operators In C | Lesson-24 | Learn C Programming From Subhash K U

In this video, we'll be learning everything about increment and decrement operators in detail.

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[durgasyamalaperuri]

Pre- increment means 1st it is increment the value and then assigned to the variable.
Post increment means 1st the value is assigned and then it is incremented.

[shreyamukkawar]

When we keep the increment operator before the variable then it is called pre increment operator and when we keep the increment operator after the variable then it is called post increment operator.
Output: a=3
b=11

[dhanyam]

when we place increment operator after the variable name it becomes post increment operator
when we place increment operator before the variable name it becomes pre increment operator

b=--a
b= a - 1= a
b= 6-1 =a
b= 5=a
(a=5)

therefore b = - -a results in 5 in the 1st case, then the value of a becomes 5
in the 2nd case --a results in 4
now value of a=4
in the 3rs case --a results in 3
now the value of a is 3

evaluating b=--a+--a+--a we get
b = 5+4+3
b=12
a=3

[savithag]

Ans: a= 3, b= 12
Preincrement is frst we have to increment the value then assign
Postincrement is frst we assign a value and then increment

[bhanuprasannareddy]

when we keep increment after the variable is called post increment operator
When we keep increment before the variable is called pre increment operator

[dhanyam]

Sir can you please show the steps involved in calculating the value of b...
As I get b =12 (I guess, I made some mistake)
and working on computer I get b=11

[sushanthchandan]

A=3 B=12
Pre increment means first we to increase the value by one and use.post increment means first we need to use that variable and incremented by one

[sravanakumar]

Hi, By using the volatile keyword for the variable a, I was getting the output value of b was 12, without volatile it was 11.

Program 1:
#include <stdio.h>
int main() {
    // Write C code here
    volatile int a = 6;
    int b = 0;
    b = --a + --a + --a;
    printf("Value of b: %d , a: %d", b, a);
    return 0;
}

Ouput : Value of b: 12, a: 3

Program 2:
#include <stdio.h>
int main() {
    // Write C code here
    int a = 6;
    int b = 0;
    b = --a + --a + --a;
    printf("Value of b: %d , a: %d", b, a); 
    return 0;
}

Output : Value of b: 11, a: 3

[thegeethaart]

Intially a=6 after pre decrement a=5 +a=4 +a=3
So, b=5+4+3=12
a=3

[dipalipotdar]

Sir please help in solving today's assignment.

[abhishekgoswami]

Sir unable to get the desired output
How it is 11?

[ashwini]

Sir don't we follow any associvity?

[kasimanvenky]

Difference between pre- increment and post- increment:
Pre- increment: here 1st we have to do increment and then assign the value.
Post increment : here 1st assign the value and then increment the value

Problem: a= 6;
b = --a + --a + --a;
Output is a=3
b= 11
1.a=6
b=--a;
a=5, b=5

2. b= --a + --a
5+4
But here we have to take update value 4 of the right side value 4 assign to the left side value

b = --a + -- a
b= 4 +4
b =8
b= --a + --a + --a
b= 4+4+3
b= 8+3
b=11
a=3, b=11
We have to do like this