In c#, the out keyword causes parameters to be passed by reference from the callee to the caller. The parameter doesn't have to be assigned going into a function but must be assigned before coming out of the function.
The out keyword causes arguments to be passed by reference. This is similar to the ref keyword, except that ref requires that the variable be initialized before being passed. To use an out parameter, both the method definition and the calling method must explicitly use the out keyword. For example:
class OutExample
{
static void Method(out int i)
{
i = 44;
}
static void Main()
{
int value = 2;
Method(out value);
// value is now 44
}
}
Although variables passed as out arguments need not be initialized prior to being passed, the called method is required to assign a value before the method returns.
The ref and out keywords are treated differently at run-time, but they are treated the same at compile time. Therefore methods cannot be overloaded if one method takes a ref argument and the other takes an out argument.
