what is difference between ++i and i+=1 from any point of view

Question

This is a question from kn king\'s c programming : a modern approach. I can\'t understand the solution given by him:-

The expression ++i is equivalent to (i          


        

Answer 1

In a normal operation without assignation:

++i and i++

increase the variable in 1. In pseudo assembly both code it is:

inc i

but If you assign the value the order of ++ is relevant:

x = i++

produce:

mov x, i
inc i

x = ++i

produce:

inc i
mov x, i

In the case of: i += 1

it will produce:

add i,1

but because compilers optimize the code it also will produce in this case:

inc i