How it's output comes to 00?

Question

int main() {
static int x=3;
if(--x){
main();
printf("%d ",x);
}
}

Answer 1

You calling main function again and again it like a recursive type x=3 in if condition if(--x) here x will decrease means if(2) which is true after that u wrote main function so control will go again to main function then it will check condition if(--x) but x was 2 so if(--1) then maing again calling same process last value will be 0 and after that 0 0 0 will return .

Answer 2

recursion tree:
If(2)
|
------------
| |
If(1) printf (x)
|
------------
| |
If(0) printf (x)
Finally x value becomes zero so it will print 00 as an output
(Inorder parsing)