[SOLVED] CS计算机代考程序代写 // inspired from: https://en.cppreference.com/w/cpp/language/explicit

// inspired from: https://en.cppreference.com/w/cpp/language/explicit

#include
using namespace std;

struct A {
int a;
A(int newA) {// converting constructor: converts from int to A
a = newA;
cout << “A::A(int) “;}A(int new1, int new2) {// converting constructor (C++11)a = new1 + new2;cout << “A::A(int,int) “;}A(const A &toCopy) {// copy constructor a = toCopy.a; // used to create a new object from an existing object of the same typecout << “A::A(A) “; }A operator+ (A toAdd) { // operators often create new objectscout << “A::operator+ “;return A(a + toAdd.a);// upon return, uses direct initialization using A::A(int)}A operator= (A toAssign) {// upon call, uses A::A(A), as A is passed by value//A operator= (A& toAssign) {// if A is passed as reference, reference initialization is used// which does not trigger the copy constructora = toAssign.a; cout << “A::operator=(A) “;return *this; // upon return, uses copy constructor A::A(A) for copy initialization of the returned value}};struct B {explicit B(int) { // cannot be used in conversion sequencecout << “B::B(int) “;}explicit B(int, int) {// cannot be used in conversion sequencecout << “B::B(int,int) “; }explicit operator bool() const {// cannot be used in conversion sequencecout << “B::operator bool() “;return true; }};int main() {cout << “A a1 = 1; uses : “;A a1 = 1; // OK: copy-initialization selects A::A(int)cout << endl;cout << “A a2(2); uses : “; A a2(2);// OK: direct-initialization selects A::A(int)cout << endl;cout << “A a3{ 4, 5 }; uses : “;A a3{ 4, 5 }; // OK: direct-list-initialization selects A::A(int, int)cout << endl;cout << “A a5(6, 7); uses : “;A a5(6, 7); // OK: direct-list-initialization selects A::A(int, int)cout << endl;cout << “A a4 = { 4, 5 }; uses : “;A a4 = { 4, 5 };// OK: copy-list-initialization selects A::A(int, int)cout << endl;cout << “A a6 = A(6) + A(7); uses : “;A a6 = A(6) + A(7); // OK: direct initialization selects A::A(int) A::A(int) A::operator+ A::A(int)cout << “a6 = ” << a6.a << endl;cout << “A a7 = a6; uses : “;A a7 = a6;// OK: copy initialization A::A(A)cout << endl;cout << “a1 = a7; uses : “;a1 = a7;// OK: a1 was already previously created, so no initialization, operator= is used cout << endl;//B b1 = 1; // error: copy-initialization does not consider B::B(int)cout << “B b2(2); uses : “;B b2(2);// OK: direct-initialization selects B::B(int)cout << endl;cout << “B b3{ 4, 5 }; uses : “;B b3{ 4, 5 }; // OK: direct-list-initialization selects B::B(int, int)cout << endl;//B b4 = {4, 5};// error: copy-list-initialization does not consider B::B(int,int)cout << “B b5 = (B)1; uses : “;B b5 = (B)1;// OK: explicit cast performs static_castcout << endl;cout << “if (b2); uses : “;if (b2);// OK: B::operator bool()cout << endl;//bool nb1 = b2;// error: copy-initialization does not consider B::operator bool()}