# order required

Rauhl Roy
Ranch Hand
Posts: 401

may i know how it is printing 1,0

when f1(i) is called i=0, but it is calling f1(i) with i=0, and when controller comes back i=0 without even telling i's values.

please let me know how this program is giving 1,0 output.

Joel McNary
Bartender
Posts: 1840
Not sure I can explain in beginner's language, but basically it's all about order of operations and how stack-based computing works.

Here's what's going on:

Line 8: i is set to zero

Line 9: i = i++ + fl(i)

Evaluation order of the right-hand-side is left to right, so:

i++ : the value of i is pushed onto the stack, and then i is incremented by 1
i is now 1, and the stack is {0}

fl(i) is evaluated, with i equal to 1. This prints the "1," and then returns zero
The return value of the function is placed onto the stack

i is now 1, and the stack is {0, 0}

The addition operation is now evaluated, popping the first two values off of the stack and adding them together
0 and 0 are popped and added, resulting in a value of 0.

This value is pushed onto the stack as the total value of the right hand side.

The assignment then takes place, setting i to the value of the right hand side, which is 0
i is now 0, and the stack is irrelevant for our purposes.

We now print the value of i, which is 0.

End result is we've printed 1,0

fred rosenberger
lowercase baba
Bartender
Posts: 12231
36
but it is calling f1(i) with i=0

this is an incorrect statement..

Rauhl Roy
Ranch Hand
Posts: 401
that is absolutely correct to call Mr. fred rosenberger