can someone explain this ?

Question

int main() {
int i=0;
cout<<(i=0?1:2?3:4);
return 0;
}

// Output 3

Answer 1

https://www.sololearn.com/Discuss/1725810/?ref=app

Answer 2

i=0 is an assignment. Maybe i==0 was meant?

i=0 returns 0, which evaluates as false.

So for the first part of the chain, the result will be 2 (equalling if (i) 1; else 2;).

2 checked for true or false, since it is not 0, is true, so the final result will be 3.

If you exchanged the 2 for a 0, the result would be 4.

Answer 3

As already said: the expression i=0 evaluates to 0, that evaluates to false. Then false ? 1 : 2 is 2. Therefore you have true ? 3 : 4 so you get 3.

Remember:
a) if(x) is same as if(x!=0)
b) if(!x) is same as if(x==0)

Parentheses and readable code are heavily underestimated!