Recursive function does not return specified value

Question

I am trying to debug a recursive function used to validate user input and return a value when the input is OK. The function looks like this:

double load_price()
{
    double price;

    Goods * tempGd = new Goods();

    cin >> price;

    while (!cin)
    {
        cin.clear();
#undef max
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
        cout << endl;
        cout << "You didn't enter a number. Do so, please: ";
        cin >> price;
    } // endwhile
    if (!tempGd->set_price(price))
    {
        cout << endl;
        cout << "The price " << red << "must not" << white << " be negative." << endl;
        cout << "Please, insert a new price: ";
        load_price();
    }
    else
    {
        delete tempGd;
        return price;
    }
}

The method set_price() of Goods class looks as follows

bool Goods::set_price(double price)
{
    if (price> 0)
    {
        priceSingle_ = price;
        priceTotal_ = price* amount_;
        return true;
    }
    return false;
}

I tried drawing the problem on a paper but all my diagrams seem to look the way my function already looks like. I think there are some problems with returns, but I do not know where.

Help would be greatly appreciated.

Where do you think the recursed result of `load_price();` is going? — WhozCraig, Dec 29 '14 at 15:25
Don’t, I repeat *don’t*, use pointers and `new` here. It’s completely meaningless, and it actually introduces a memory leak into your code. — Konrad Rudolph, Dec 29 '14 at 15:26
@WhozCraig I honestly have no idea. It seems to be burried somewhere within the function itself. — Andrew, Dec 29 '14 at 15:28
@KonradRudolph Thanks for the tip, m8, replaced the Goods object on heap with a stack object. — Andrew, Dec 29 '14 at 15:29
Doesn't your compiler warn about not returning a value on all code paths? — Lightness Races in Orbit, Dec 29 '14 at 17:11
@LightnessRacesinOrbit No, it did not. I am using Visual Studio 2013 Express. However another user recommended a non-recursive solution and I used that. — Andrew, Dec 30 '14 at 08:33

score 5 · Accepted Answer · answered Dec 29 '14 at 15:25

5

You're not using the return value of the recursive call. You need to do:

return load_price();

answered Dec 29 '14 at 15:25

Barmar

741,623
53
500
612

Shall my return price; be replace with said code, Barmar? – Andrew Dec 29 '14 at 15:26
@OndřejŠimon No, all of your recursive calls should be replaced. – Captain Giraffe Dec 29 '14 at 15:28
@CaptainGiraffe Oh I see, replacing the recursive call load_price() with return load_price(); as Barmar recommended worked. Thank you, guys. – Andrew Dec 29 '14 at 15:31

Hans Klünder · Answer 2 · 2014-12-29T15:47:16.110

1

Who talked you into using recursion for that problem?

#undef max
double load_price()
{
   for(;;) {
      double price;
      cin >> price;
      if (!cin)
      {
         cin.clear();
         std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
         cout << endl;
         cout << "You didn't enter a number. Do so, please: ";
         continue;
      }
      if (!Goods().set_price(price))
      {
         cout << endl;
         cout << "The price " << red << "must not" << white << " be negative." << endl;
         cout << "Please, insert a new price: ";
         continue;
      }
      return price;
   }
}

edited Dec 29 '14 at 15:47

answered Dec 29 '14 at 15:41

Hans Klünder

2,176
12
8

Thank you for the iterative solution. To be honest I was trying to find one but could not wrap my head around it. I will use yours, if you don't mind. I do not really like recursion, just could not figure the iterative solution out. – Andrew Dec 29 '14 at 15:50
Of course, feel free to use it. I won't post anything here if I don't want people to use it. – Hans Klünder Dec 29 '14 at 15:52
Thank you once again, Hans. I altered my other 2 recursive methods using your template, methods I used to check for inserted ID and amount of Goods. – Andrew Dec 29 '14 at 16:04

Recursive function does not return specified value

2 Answers2

Linked

Related