what is the output of this program??

Question

#include<iostream>
#include<stack>
using namespace std;
int main() {
stack<int> s;
s.push(1);
s.push(2);
s.empty();
s.push(3);
cout<< s.size();
}

Answer 1

The output is 3. If you're asking WHY it outputs 3, the empty function does not empty the stack; it return 1 if it's empty and 0 if it's not. Thus, after pushing 3 numbers into the stack, the size of the stack is 3 and outputs 3.