About assigning to references

[maluk]

I am reading about C++ references. I came about the code that cannot compile. Here is the code:

int& i = 1 ;       // this will cause a compiler error
const int& j = 1 ; // this works

On my compiler, it says Initialization of non-const reference type 'int&' from rvalue of type 'int'. Can someone tell me the reason for this? What does it say in the C++ Standard regarding this?

Just for clarification, is the numeric literal '1' a constant?


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[ArkM]

In C++ reference initializer must be one of:
1. lvalue (except a bit-field)...
2. has a class type (to bind directy) and can be implicitly converted to an lvalue of ref. type...
3. otherwise, the reference shall be to a non-volatile const type.

You have rule #3 violation...

Semantics: 1 is not an object in memory, it's integer one value. You can't redefine integer one via reference to 1. But:

/* if */ int& oneref = 1; // is OK, and oneref refers to 1
/*then*/ oneref = 2; // is OK too, but now 2 == 1?

 

[ArkM]

Apropos, it's not an assigning to reference, it's a reference initialization. Assigning != initialization.