Under what circumstances can you return a reference from a method?
When to use return by reference:
- When returning a reference parameter.
- When returning a member of an object that was passed into the function by reference or address.
- When returning a large struct or class that will not be destroyed at the end of the function (e.g. one that was passed in by reference)
Can a function return a reference C++?
A C++ function can return a reference in a similar way as it returns a pointer. When returning a reference, be careful that the object being referred to does not go out of scope. So it is not legal to return a reference to local var.
How do you return a value from a function C++?
To return a value back to the caller, two things are needed.
- First, your function has to indicate what type of value will be returned. …
- Second, inside the function that will return a value, we use a return statement to indicate the specific value being returned to the caller. …
- Functions are not required to return a value.
Can we create array of reference?
There shall be no references to references, no arrays of references, and no pointers to references. References are not objects. They don’t have storage of their own, they just reference existing objects. … If you want a light-weight object that references another object then you can use a pointer.
Does C++ return by value?
C++ functions can return by value, by reference (but don’t return a local variable by reference), or by pointer (again, don’t return a local by pointer). When returning by value, the compiler can often do optimizations that make it equally as fast as returning by reference, without the problem of dangling references.
Can we return a global variable by reference?
It’s possible to return a reference from a function. … But you can return a reference to a global variable. Or, if the function is a member function, you can return a reference to a member variable.
Can C++ function return multiple values?
In C or C++, we cannot return multiple values from a function directly.
How do you return a null reference in C++?
C++ has value semantics. There are nullptr s but there is no null value. A reference always references something. Ergo, there cannot be a reference to null.
However, different strategies can be considered:
- Return iterators: use std::end(items) as the null value.
- Return by value.
- Throw an exception if no element is valid.
Does return end a function C++?
The return statement stops execution and returns to the calling function. When a return statement is executed, the function is terminated immediately at that point, regardless of whether it’s in the middle of a loop, etc.
What does return 0 do in C++?
The return value of the main function is considered the “Exit Status” of the application. On most operating systems returning 0 is a success status like saying “The program worked fine”. In C++ it is optional to type ” return 0; ” at the end of the main function and the compiler includes it automatically.
What does return 1 do in C++?
returning different values like return 1 or return -1 means that program is returning error . When exit(0) is used to exit from program, destructors for locally scoped non-static objects are not called. But destructors are called if return 0 is used.
How do you return an array in C++?
C++ does not allow to return an entire array as an argument to a function. However, you can return a pointer to an array by specifying the array’s name without an index.
How do I return a character?
If you want to return a char* from a function, make sure you malloc() it. Stack initialized character arrays make no sense in returning, as accessing them after returning from that function is undefined behavior. char* charP = createStr(); Would be correct if your function was correct.