c++ reference parameters functions [closed]

问题

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Closed 6 years ago.

Im having trouble with the reference parameters. The values in getStockInfo are supposed to be stored in reference parameters. I dont know how to do that so that displayStatus accepts those as arguments. Whenever i put something into getStockInfo in main it gives me the error More than one onstance of overloaded function "getStockInfo" matches the argument list.

#include <iostream>
#include <iomanip>
using namespace std;

void getStockInfo(int &, int&, double&);
void displayStatus(int &, double &);

int main()
{
   int spoolsOrdered;
   int spoolsStock;
   double specialCharges;

   cout << "Middletown Wholesale Copper Wire Company" << endl;

   getStockInfo(spoolsOrdered, spoolsStock, specialCharges);
}

void getStockInfo(int &spoolsOrdered, int &spoolsStock, double specialCharges)
{
   char ship; 

   cout << "How many spools would you like to order: ";
   cin >> spoolsOrdered;

   //Validate the spools ordered 
   while(spoolsOrdered < 1)
   {
      cout << "Spools ordered must be at least one" << endl;
      cin >> spoolsOrdered;
   }

   cout << "How many spools are in stock: ";
   cin >> spoolsStock;

   //Validate spools in stock
   while(spoolsStock < 0)
   {
       cout << "Spools in stock must be at least 0" << endl;
       cin >> spoolsStock;
   }

   cout << "Are there any special shipping charges? ";
   cout << "Enter Y for yes or another letter for no: ";
   cin >> ship;

   //Validate special charges
   if(ship == 'Y' || ship == 'y')
   {
    cout << "Enter the special shipping charge: $";
    cin >> specialCharges;
   }
   else
   {
    specialCharges = 10.00;
   }
}

void displayStatus(int &backOrder, double &subtotal, double &shipping, double &total)
{
}  

回答1:

Your declaration and definition of getStockInfo differ: The final parameter in one is a reference and in the other it is not.

void getStockInfo(int &, int&, double&);
...
void getStockInfo(int &spoolsOrdered, int &spoolsStock, double specialCharges)

A similar issue occurs with displayStatus: Here the number of parameters is different.

void displayStatus(int &, double &);
...
void displayStatus(int &backOrder, double &subtotal, double &shipping, double &total)

The error message occurs since the compiler can't determine whether you are telling it to call getStockInfo(int &, int&, double&) (which may come from another file) or the one defined in this file void getStockInfo(int &, int&, double).

Note having multiple versions is not "wrong". However calling one in a way that the compiler doesn't know which one to call is.

回答2:

Your parameter list in the prototype doesn't match the one in the definition.

void displayStatus(int &, double &);

vs

void displayStatus(int &backOrder, double &subtotal, double &shipping, double &total)
{
}  

来源：https://stackoverflow.com/questions/15755391/c-reference-parameters-functions