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Various techniques for returning multiple values include: Returning a tuple of values. This is conventional in languages (such as Python) that have a built-in tuple data type and special syntax for handling these: in Python, x, y = f() calls the function f returning a pair of values and assigns the elements of the pair to two variables ...
In C and C++, return exp; (where exp is an expression) is a statement that tells a function to return execution of the program to the calling function, and report the value of exp. If a function has the return type void , the return statement can be used without a value, in which case the program just breaks out of the current function and ...
Structures aggregate the storage of multiple data items, of potentially differing data types, into one memory block referenced by a single variable. The following example declares the data type struct birthday which contains the name and birthday of a person.
For returning a value of one of several types, a tagged union can be used instead; the most common cases are nullable types (option types), where the return value can be null to indicate failure. For exception handling, one can return a nullable type, or raise an exception.
The void type, in several programming languages derived from C and Algol68, is the return type of a function that returns normally, but does not provide a result value to its caller. Usually such functions are called for their side effects , such as performing some task or writing to their output parameters.
POD return values 33–64 bits in size are returned via the EAX:EDX registers. Non-POD return values or values larger than 64-bits, the calling code will allocate space and passes a pointer to this space via a hidden parameter on the stack. The called function writes the return value to this address. Stack aligned on 4-byte boundary. stdcall ...
In C++ they are also available for values of class types by declaring the appropriate return type for the assignment operator. In Python, assignment statements are not expressions and thus do not have a value. Instead, chained assignments are a series of statements with multiple targets for a single expression.
This is also useful for returning multiple values from a function. Pointers can also be used to allocate and deallocate dynamic variables and arrays in memory. Since a variable will often become redundant after it has served its purpose, it is a waste of memory to keep it, and therefore it is good practice to deallocate it (using the original ...