CODEWITHSUNDEEP
c++returnlanguage-lawyervoid
skydoor
skydoor

Reputation: 25868

Can I use a return statement in a function returning void?

I have to return to the previous level of the recursion. is the syntax like below right? 

void f()
{
   // some code here
   //
   return;
}

Upvotes: 61

Views: 121637

Answers (9)

icktoofay
icktoofay

Reputation: 128991

Yes, you can use that code to return from the function.

Upvotes: 10

magrif
magrif

Reputation: 480

Yes, for example:

void foo()
{
    // do smth
}

and then

void bar(bool condition)
{
    if (condition) {
        return foo(); //its ok
    }
    // else do smth
}

Upvotes: 1

ThinkingInBits
ThinkingInBits

Reputation: 11422

Yes, sometimes you may wish to return void() instead of just nothing.

Consider a void function that wants to call some pass-through void functions without a bunch of if-else.

return 
  InputEvent == E_Pressed ? Controller->Grip() :
  InputEvent == E_Released ? Controller->Release() :
  InputEvent == E_Touched ? Controller->Touch() : void();

Upvotes: 4

dromodel
dromodel

Reputation: 10193

As everyone else said, yes you can. In this example, return is not necessary and questionably serves a purpose. I think what you are referring to is an early return in the middle of a function. You can do that too however it is bad programming practice because it leads to complicated control flow (not single-entry single-exit), along with statements like break. Instead, just skip over the remainder of the function using conditionals like if/else().

Upvotes: 1

Peter Alexander
Peter Alexander

Reputation: 54270

Yes, you can return from a void function.

Interestingly, you can also return void from a void function. For example:

void foo()
{
  return void();
}

As expected, this is the same as a plain return;. It may seem esoteric, but the reason is for template consistency:

template<class T>
T default_value()
{
  return T();
}

Here, default_value returns a default-constructed object of type T, and because of the ability to return void, it works even when T = void.

Upvotes: 121

Buhake Sindi
Buhake Sindi

Reputation: 89169

The simple answer to this is YES! C++ recognise void method as a function with no return. It basically tells the compiler that whatever happens, once you see the return; break and leave the method....

Upvotes: 3

user147373
user147373

Reputation:

Yes, that will return from the function to the previous level of recursion. This is going to be very basic explanation, but when you call a function you are creating a new call stack. In a recursive function you are simply adding to that call stack. By returning from a function, whether you return a value or not, you are moving the stack pointer back to the previous function on the stack. It's sort of like a stack of plates. You keep putting plates on it, but than returning moves the top plate.

You could also verify this by using a debugger. Just put a few break points in your code and step through it. You can verify yourself that it works.

Upvotes: 3

Craig
Craig

Reputation: 1219

You shouldn't have to have the return there, the program will return to the previous function by itself, go into debug mode and step through and you can see it yourself. On the other hand i don't think having a return there will harm the program at all.

Upvotes: 2

Ignacio Vazquez-Abrams
Ignacio Vazquez-Abrams

Reputation: 798516

Sure. You just shouldn't be returning an actual value.

Upvotes: 15

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