c – 文字值的范围是什么,编译器如何为其分配内存？

Foo getFoo() {return Foo();}

int func()
{
    getFoo().bar();   // Creates temporary.
    // before this comment it is also destroyed.
    // But it lives for the whole expression above
    // So you can call bar() on it.
}

int func2()
{
    Foo const& tmp = getFoo();  // Creates temporary.
                                // Does not die here as it is bound to a const reference.

    DO STUFF
}  // tmp goes out of scope and temporary object destroyed.
   // It lives to here because it is bound to a const reference.

How does the compiler allocate memory to a temporary object?

未定义到编译器.
但是在堆栈帧上分配更多的内存并将其保存在那里真的很容易.然后销毁它并减小堆栈帧的大小(尽管这个答案对你不应该做的底层硬件做了很多假设(最好只把它想象为编译器做魔术)).

What is the scope of a temporary object?

临时对象一直存在到表达式的末尾(通常是;),除非它绑定到const引用.如果它绑定到const引用,那么它仍然存在于引用所属范围的末尾(有一些例外(如构造函数)).

Why can’t we get its address with an &12 in its scope?

在问题12中不是临时对象.它是一个整数字面值.