The for loop will run from 0 to 3 as the range is till 4.
Initialally, the i is 0.
Then i will become 1. 1 is added to result
Then i will become 2. 2 is added to result.
Similarly i will become 3. Now 3 is added to the result.
So result will be 0+1+2+3 i.e. 6
The output is 4.
It is 4 because the for loop is executed 4 times. Each time adding 1 to the variable "res" which starts at 0.
If you want 6 as the output, either make rs == 2 or x ==6
