C++ lambda copy value in capture-list

Question

I have a program as below:

int main()
{
    int val = 4;
    auto add = [val](int a)->int{
        val += 2;
        return a+val;
    };
    cout <<         


        

Answer 1

Just capture it by reference, it will work !!

 auto add = [&val](int a) -> int{ 
       //
}