将数组从C ++构造函数传递给函数

Question

If I have a class with a constructor containing an array and I want to pass each member of this array to a function of this class for an addition how can I do so?

eg Constructor implementation

person::person 
{
  double NoPerson[150]; //no of people  
  for(int j=0;j<=150;j++)
  {
    NoPerson[j]=1.00;//has to set to 1 pound
  }

  double person::aveWage(double NoPerson[])
  {
    double total;
    double NoPerson[150];

    using namespace std;

    for(int i=0;i<=150 ;i++)
    { 
      total=total+cashCus[i];
    }
    cout<<"total cash for all customers "<<total <<endl;
}

Does anyone know how this can be achieved?

Answer 1

Does it really have to be an array? If so you need to pass the size along with it, eg int add(int[] items, int size) . This tutorial covers the basics of arrays: http://www.cplusplus.com/doc/tutorial/arrays/

However, arrays are more of a "plain C" thing. If you are using C++, you're almost always better off using a vector .

Answer 2

I don't know if I understand you right, but it seems to me that you have an array ( NoPerson ) that you want to initialize in the constructor, and then use from the other functions in your class.

In that case you should not make it a local variable, because then the other function in the class can't access it. Instead you make it a member variable of the class, just like the functions.

Something like this:

class Person
{
public:
    Person()
        {
            for (int i = 0; i < 150; i++)
                NoPerson[i] = 1;
        }

    double total()
        {
            double total;

            for (int i = 0; i < 150; i++)
                total += NoPerson[i];

            return total;
        }

private:
    // Variables and functions in the 'private' section can only be
    // referenced by the function in this class.

    int NoPerson[150];  // This is a member variable
}

As you can see in the above example, the variable NoPerson is defined in the class and not in the functions . This makes it accessible to all functions in the class.

Answer 3

your code is kind of broken. You have actually three different arrays called 'NoPerson' in the code, one is local to the constructor, one is the argument to aveWage, and then you have a locally declared NoPerson array within aveWage. Additionally, you are not using the arrays for anything, and the array in the constructor is deleted when you leave the constructor. If you want to call aveWage from the constructor with NoPerson array as the argument to aveWage, you can do this, but the local declaration in aveWage will mask it.

Answer 4

1) You got your array bounds wrong (it should be < 150 ).

2) In C++98/03, you cannot initialize member arrays; in C++11 you can (though initialzing 150 non-zero values is cumbersome): person::person() : NoPerson{1., 1., 1.} { } (actually 150 elements). (It's unlikely that this problem would survive a proper design revision, though.)

3) the aveWage loop could be written with std::accumulate (eg std::cout << "total = " << std::accumulate(cashCus, cashCus + 150, 0) << std::endl; . Currently your code is broken because you never initialize total .