CODEWITHSUNDEEP
c++
Manan Shah
Manan Shah

Reputation: 35

C++ unused variable warning even when I returned it at the end of function

Table::Table(int n): maxGuests(n)
{
    int numGuests = 0;
}
int Table::maxOccupancy(void)
{
    return maxGuests;
}

int Table::currentOccupancy(void)
{
    return numGuests;
}

As in the above code, I'm getting an unused numGuests warning, even after returning it at the end of my accessor. Why would that be?

Thanks :)

Upvotes: 3

Views: 2916

Answers (4)

Rizwan
Rizwan

Reputation: 3686

In the code

Table::Table(int n): maxGuests(n)
{
int numGuests = 0;
}

A local variable numGuests is defined, which is not the class property. And this is not used anywhere. Hence you are getting the warning. Remove int in the statement int numGuests = 0; should resolve this problem.

OR better you can update your code to include this property in the initializer list itself like:

Table::Table(int n) : maxGuests(n), numGuests(0)
{
}

Upvotes: 9

Walter
Walter

Reputation: 45474

The local variable numGuests in the snippet

Table::Table(int n): maxGuests(n)
{
    int numGuests = 0;
}

has not been used. Presumably you want instead

struct Table
{
    ...
    int numGuests = 0;      // default value
    const int maxGuests;
    Table(int n) : maxGuests(n) {}
};

Upvotes: 8

tadman
tadman

Reputation: 211700

You're creating a variable that "shadows" the property you're trying to assign. I'm not sure why you're using two completely different initialization methods here, but you can simplify the code and fix the bug like this:

Table::Table(int n) : maxGuests(n), numGuests(0)
{
}

Whenever practical, initialize your properties like that. Doing it in code is usually reserved for cases where it's not clear what value will be assigned, some computation is required, or you need to delegate to a function to do it.

Upvotes: 4

Lex Sergeev
Lex Sergeev

Reputation: 241

You create a local variable with the same name as a class member. Just remove int to get what you want:

Table::Table(int n): maxGuests(n)
{
    numGuests = 0;
}

Upvotes: 4

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