C++: Array as Function Formal Parameter Gets me Errors

Question

I'm in a computer science class in college. I'm working on an assignment that isn't due soon, but I'm running into a problem and I'm tired of waiting on my teacher to respond to my emails. We use Visual Studio 2015 to learn to code with C++, and have gotten through user-defined functions, arrays and structs. We haven't done anything with classes or anything, and all the information I've found on the errors I'm getting seem to involve these and are thus no help to me.

Whenever I run my program I get the following errors:

"LNK2019 unresolved external symbol "void __cdecl takeOrder(int,int,struct menuItemType * const)" (?takeOrder@@YAXHHQAUmenuItemType@@@Z) referenced in function _main

LNK1120 1 unresolved externals"

both errors are said to be in "line 1".

The documents on the Visual Studio site are a bit too vocab heavy and I'm not understanding all the information there, but I think it has something to do with my declaration of variables. That's the only thing that makes sense.

I don't have a great understanding of arrays, but I think I'm using them right. I've double, triple, quadruple checked the textbook and my notes and my spelling, and I don't know what I'm missing. Below is the code in its entirety (save some of the // stuff that just makes it longer).

#include <iostream>
#include <string>
#include <fstream>
#include <iomanip>
#include <cstring>

using namespace std;

struct menuItemType
{
    string itemName;
    double itemPrice;
};

void read(menuItemType menuList[], int&);
void showMenu(menuItemType menuList[], int&);
void takeOrder(int, int, menuItemType menulist[]);

int main()
{
    int counter = 0;
    menuItemType menuList[10];
    int order[10] = { 0,0,0,0,0,0,0,0,0,0 };
    double totalBill = 0;
    double tax = 0;

    cout << fixed << setprecision(2) << showpoint;
    cout << "Welcome to Hold-ye-Overs, a delightful place to eat with food\nmade from one hundred percent actual food!\n";

    read(menuList, counter);
    showMenu(menuList, counter);
    takeOrder(order[10], counter, menuList);

    return 0;
}

void takeOrder(int order[], int counter, menuItemType menuList[])
{
    int amount_of_item;
    int choice;
    bool flag = true;
    char orderMore;

    while (flag == true)
    {
        cout << "Please enter the number for the item you would like to have." << endl;
        cin >> choice;
        cout << "Please enter the number of " << menuList[choice - 1].itemName << "s you would like to order." << endl;
        cin >> amount_of_item;
        order[choice - 1] = order[choice - 1] + amount_of_item;
        cout << "Would you like to order more items? y/n" << endl;
        cin >> orderMore;
        if (orderMore == 'y' || orderMore == 'Y')
            flag = true;
        else
            flag = false;
    }

}
void read(menuItemType menuList[], int& counter)
{
    ifstream in;
    in.open("menu.txt");
    char temp = char();
    int i = 0;

    while (!in.eof())
    {
        getline(in, menuList[i].itemName);
        in >> menuList[i].itemPrice;
        //cout << menuList[i].itemName << " " << menuList[i].itemPrice << endl;
        in.get(temp);//to pick up endl after the price
        ++i;
        counter++;
    }
    in.close();
}

void showMenu(menuItemType menuList[], int& counter)
{
    cout << fixed << setprecision(2) << showpoint;
    int i = 0;
    for (i = 0; i < counter; i++)
    { cout << left << setw(2) << i + 1 << " :" << left << setw(20) << menuList[i].itemName;
    cout << right << setw(1) << "$" << left << setw(7) << menuList[i].itemPrice << endl;
    }

}

Possible duplicate of [What is an undefined reference/unresolved external symbol error and how do I fix it?](http://stackoverflow.com/questions/12573816/what-is-an-undefined-reference-unresolved-external-symbol-error-and-how-do-i-fix) — Ken White, Dec 04 '16 at 03:17
Look at your prototype of `takeOrder` and the implementation of `takeOrder`. See a difference in the parameters? — PaulMcKenzie, Dec 04 '16 at 03:17
There is a mismatch between the declaration and definition of `takeOrder`. — R Sahu, Dec 04 '16 at 03:18
Don't use forward declarations except for mutually recursive functions. Put `main` function last. Problem fixed. [Out of curiosity: where did you learn that hit-me-please-oh-please-hit-me style of coding? If it was book, BURN IT.] — Cheers and hth. - Alf, Dec 04 '16 at 03:24
Your forward declaration does not match the parameter list of your implementation — Yan Zhou, Dec 04 '16 at 06:10

score 0 · Accepted Answer · answered Dec 04 '16 at 04:26

I can see two places you need to correct things if you want to pass array to function takeOrder.

definition of function takes array so declaration need to change to void takeOrder(int[], int, menuItemType menulist[]);
change usage in main function to takeOrder(order, counter, menuList); as your function is accepting array not int (order[10] passes integer)

If you want to pass integer change definition of function to takeOrder(int order, int counter, menuItemType menuList[])

Thanks! That did the trick. I guess I wasn't understanding how to properly format the parameters so they would work properly. Thanks again! — Joshua Frazer, Dec 04 '16 at 05:32

C++: Array as Function Formal Parameter Gets me Errors

1 Answers1