JuniorTheoryCommon

What does the program print?

C++

#include <iostream>

int main() {
    int n = 2;
    int a = 1 << n + 1;
    int b = n > 1 ? 10 : 20 + 1;
    std::cout << a << ' ' << b << '\n';
}

8 10

Expecting 5 for a: + has higher precedence than <<, so 1 << n + 1 is 1 << 3, which is 8.
Expecting 11 for b: ?: has lower precedence than +, so 20 + 1 is the whole third operand, and b gets 10.

Where would you add parentheses so that a becomes 5 and b becomes 11?
Why does std::cout << n > 1; fail to compile while std::cout << (n > 1); works?

JuniorTheoryCommon

C++

#include <iostream>

int main() {
    int n = 2;
    int a = 1 << n + 1;
    int b = n > 1 ? 10 : 20 + 1;
    std::cout << a << ' ' << b << '\n';
}

8 10

Expecting 5 for a: + has higher precedence than <<, so 1 << n + 1 is 1 << 3, which is 8.
Expecting 11 for b: ?: has lower precedence than +, so 20 + 1 is the whole third operand, and b gets 10.

Where would you add parentheses so that a becomes 5 and b becomes 11?
Why does std::cout << n > 1; fail to compile while std::cout << (n > 1); works?