About for-loop's first argument

Question

It works well when I put i=0 and printf in the for-loops first argument.

https://code.sololearn.com/cOmt1bCE5Q3m/?ref=app

But if I move the definition of i int for-loop, It just sent me an error.

https://code.sololearn.com/cqAg5xoO4BOY/?ref=app

Can anyone explain why?

thx.

Answer 1

左其右
I believe the problem is the same as if you do this:

int i =1, accumulator = 0, printf('hello');

The compiler sees the printf as a declaration of an int so you get an error.

Answer 2

Ulisses Cruz
I knew.

But how can I declare a variable and run a function simultaneously
at the start of the for-loop.

Answer 3

左其右
The fist part of the for loop is for variables initialization,
If you need to run a function at the start of a for loop,
run it before the for loop, like this:

printf('Hello'); // print function
for(int i = 0; i < 10; i++){
// do something
}