Cleanup and project

Questions 1 to 5 of 8

1. 1. A class Noisy prints open NAME in its constructor and close NAME in its destructor. main runs this block: { Noisy a("a"); Noisy b("b"); std::cout << "end of block\n"; }. Put the printed lines in the order the program prints them.

   Use the arrows to put the steps in order.

   1. 1.open b↑↓
   2. 2.end of block↑↓
   3. 3.close b↑↓
   4. 4.close a↑↓
   5. 5.open a↑↓
2. 2. Put these steps in the order they happen when a function creates a local std::lock_guard and then hits an early return.

   Use the arrows to put the steps in order.

   1. 1.The guard's destructor runs and unlocks the mutex↑↓
   2. 2.The function creates a local std::lock_guard, and its constructor locks the mutex↑↓
   3. 3.A return statement leaves the function's scope early↑↓
3. 3. What does this program print? ``cpp #include <iostream> #include <string> #include <utility> struct Tag { std::string name; explicit Tag(std::string n) : name(std::move(n)) { std::cout << "+" << name; } ~Tag() { std::cout << "-" << name; } }; void f() { Tag a{"a"}; Tag b{"b"}; throw 1; } int main() { try { f(); } catch (int) { std::cout << " caught"; } std::cout << '\n'; } ``

   +a+b-a-b caught+a+b caught-b-a+a+b-b-a+a+b-b-a caught
4. 4. Why does this code fail to compile? ``cpp #include <cstddef> class IntBuffer { public: explicit IntBuffer(std::size_t size) : data_(new int[size]{}) {} ~IntBuffer() { delete[] data_; } IntBuffer(const IntBuffer&) = delete; private: int* data_; }; int main() { IntBuffer a(3); IntBuffer b = a; } ``

   new int[size]{} is invalid syntax, so the constructor cannot be compiledThe destructor must not call delete[], so the class is wrong before the copyThe copy constructor is deleted, so IntBuffer b = a; is an error, because two copies would both free the same arrayThe class has no default constructor, so IntBuffer b = a; has nothing to start from
5. 5. The code below compiles, but -Wall prints a warning. What is the cause? ``cpp class Pen { public: Pen(int price, int qty) : qty_{qty}, price_{price} {} private: int price_; int qty_; }; ``

   qty_ and price_ are swapped, so the stored values are wrong at run timeThe initializer list is written in a different order from the declarations, so -Wreorder warns; members are set in declaration order, with price_ firstBrace initialization is not allowed for class membersA class with a two-argument constructor needs a default constructor as well