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Can references be const?
References are inherently const , that is you can’t change what they refer to. There are ‘ const references’ which are really ‘references to const ‘, that is you can’t change the value of the object they refer to. They are declared const int& or int const& rather than int& const though.
Can be passed as argument to a function by reference?
Pass-by-reference means to pass the reference of an argument in the calling function to the corresponding formal parameter of the called function. The called function can modify the value of the argument by using its reference passed in. The following example shows how arguments are passed by reference.
Why do we pass or return variables by const * or const&?
We pass by const reference to avoid making a copy of the object. When you pass a const reference, you pass a pointer (references are pointers with extra sugar to make them taste less bitter). And assuming the object is trivial to copy, of course.
Is const reference faster than reference?
If you’re uncertain if a non-fundamental type is fast to pass by value, pass it by const reference. Pass non-pointer, non-fundamental data type variables (such as structs) by (const) reference, unless you know that passing it by value is faster.
Why is passing arguments as const references premature?
It is about optimising before the problem is understood, before the runtime is understood, and often making code less readable and less maintainable for dubious results.
Which is better passing by const or by value?
Passing by const reference is the preferred way to pass around objects as a smart alternative to pass-by-value. When you pass by const reference, you take the argument in by reference (avoiding making any copies of it), but cannot make any changes to the original object (much as would happen when you would take the parameters in by value).
When to pass arguments as const references in C + +?
It actually improves both, because it tells me that a call will not modify the object passed in. So adding “const&” right when you write the code is NOT PREMATURE. TL;DR: Pass by const reference is still a good idea in C++, all things considered. Not a premature optimization. TL;DR2: Most adages don’t make sense, until they do.
What happens when you pass by const reference?
When you pass by const reference, you take the argument in by reference (avoiding making any copies of it), but cannot make any changes to the original object (much as would happen when you would take the parameters in by value). If you consider these three functions: