I am learning about lambdas in modern C++ and I am trying to understand about captures.

My lambda below captures the variable x by value. However, why do I get the output value 11 even through I set 100 as a new value for x prior to the call to add_to_x(int).

Q1 Does the resolution of a by-copy captured variable x in a lambda happen only at the point of the lambda definition and not at its usage which is why it has used x=1 rather than the x=100?

int main(int argc, char** argv) {

    int x = 1;

    auto add_to_x = [x] (int i) { 
            return i + x;
    };

    x = 100;

    cout << "add_to_x=" << add_to_x(10) << endl;

    // prints "add_to_x=11" but I was expecting "add_to_x=110"
}

However, if I capture by-reference, it used x=100 and I got 110.

Q2 How did it happen that by adding the & to the captured variable (turning it to a capture by-reference) it suddenly considered to use the x=100?

int main(int argc, char** argv) {

    int x = 1;

    auto add_to_x = [&x] (int i) { 
            return i + x;
    };

    x = 100;

    cout << "add_to_x=" << add_to_x(10) << endl;

    // prints "add_to_x=110"
}

I tried a couple of combinations but it behaved the same.