C++-struct A.（1）A a; (2) int b = a(2); (3)int b = A(1,2).让这3个代码可以编译通过，求struct A的实现方法?

Question

struct A.（1）A a; (2) int b = a(2); (3)int b = A(1,2).让这3个代码可以编译通过，求struct A的实现方法?

Answer 1

struct A
{
A(){}
A(int a,int b){}
int operator()(int b)
{
return 3;
}
operator int()
{
return 3;
}
};
2种构造函数、函数调用操作符、类型转换操作符即可