C++ 自动& vs 自动 - C++ auto& vs auto

问题：

When creating local variables, is it correct to use (const) auto& or auto ?创建局部变量时，使用(const) auto&或auto是否正确？

eg:例如：

SomeClass object;
const auto result = object.SomeMethod();

or const auto& result = object.SomeMethod();或const auto& result = object.SomeMethod();

Where SomeMethod() returns a non-primitive value - maybe another user-defined type. SomeMethod() 返回一个非原始值 - 可能是另一个用户定义的类型。 My understanding is that const auto& result is correct since the result returned by SomeMethod() would call the copy constructor for the returned type.我的理解是const auto& result是正确的，因为 SomeMethod() 返回的结果会调用返回类型的复制构造函数。 Please correct me if I am wrong.如果我错了，请纠正我。

What about for primitive types?对于原始类型呢？ I assume const auto sum = 1 + 2;我假设const auto sum = 1 + 2; is correct.是正确的。

Does this also apply to range based for loops?这是否也适用于基于范围的 for 循环？

for(const auto& object : objects)

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解决方案：

参考： https://stackoom.com/en/question/21Htc