JuniorTheoryCommon

What does the program print?

JavaScript

const stack = [];
stack.push(1);
stack.push(2);
stack.push(3);
const a = stack.pop();
const b = stack.pop();
console.log(a, b);

3 2

Expecting 1 2: pop takes from the end of the array, so the last value pushed comes out first — a stack is last in, first out.
Expecting 3 3: pop removes the element it returns, so the second pop sees [1, 2] and returns 2.