我目前正在尝试将“main”函数的内容移动到它自己的函数中，这样我就可以重复操作，也可以有更多的选项来选择何时发生什么。一旦函数完成，我还想在每次购买时增加一个整数，这样就可以用某种库存命令来检查它。
我犯了一个错误，把我以前在main中的东西复制粘贴到我想成为它自己的函数中。不幸的是，这实际上是我第一次尝试声明一个不是这个网站上其他人给我的函数，所以我真的不知道如何声明它们。我猜声明不正确/缺少数据，导致问题。
代码：

#include <cs50.h>
#include <stdio.h>
#include <string.h>

//Attempting to declare the function early, which is the only thing CS50 has taught me about custom functions thus far.
void itemshop(int buckaroonies);

//Struct given to me in another post
struct item
    {
        string name;
        int price;
        string description;
    };

//Part of aformentioned struct
int find_item(string item_name, struct item items[], size_t num_items)
{
    for (size_t i = 0; i < num_items ; i++)
    {
        if (0 == strcmp(items[i].name, item_name))
        {
            return i;
        }
    }
    //Item not available
    return -1;
}

int main(void)
{
    //Item struct
     struct item items[] = {
        {"Matchbox", 50, "They're cheap, and they'll keep you warm."},
        {"Wool Hat", 125, "A nice, handknit, cozy hat. Thank my ma for that!"},
        {"Heavy Coat", 250, "This coat'll keep you cozy through the night no matter the situation!"},
        {"Canned Food", 25, "It don't taste too good, but it'll last you a lifetime. Eat up!"}
    };
    const size_t num_items = sizeof(items) / sizeof(items[0]);

    //Integers for items once they are purchased
    int buckaroonies = 500;
    int matchb = 0;
    int woolh = 0;
    int heavyc = 0;
    int canf = 0;

    itemshop(int buckaroonies);
}

//This is probably the worst part, I just copy-pasted what I had in main into this function, and likely declared it incorrectly as well
void itemshop(int buckaroonies)
{
    //Dialogue and selection
    printf("Hey chum, welcome to the item shop. You've got a handful 'o coin on ya, huh?\nYou came to the right place, we got the best wares in town!\n\n");
    printf("Store:\n\nMatchbox - 50\nWool Hat - 125\nHeavy Coat - 250\nCanned Food - 25\n");
    string select = get_string ("What'll it be? You have %i buckaroonies, pal.\n", buckaroonies);
    string description[] = { "They're cheap, and they'll keep you warm.\n", "A nice, handknit, cozy hat. Thank my ma for that!\n", "This coat'll keep you cozy through the night no matter the situation!\n", "It don't taste too good, but it'll last you a lifetime. Eat up!" };

    //Get item details from selection, error comes from here
    int index = find_item(select, items, num_items);

    //Return dialogue based on selected item
    if (-1 == index)
    {
        printf("We aint got that, pal.\n");
    }
    else
        {
            char c = get_char ("That %s'll cost ya %i buckaroonies. %s You want it?\n", items[index].name, items[index].price, items[index].description);

            if(c == 'y' || c == 'Y')

                {
                    printf("Pleasure doing business with you, pal. -%i Buckeroonies\n", items[index].price);
                    buckaroonies = buckaroonies - items[index].price;
                }
            else if (c == 'n' || c == 'N')
                {
                    printf("Alright, feel free to keep browsing.\n");
                }
            else
                {
                    printf("Hey, uh... I don't know what that means.\n");
                }
        }
}

字符串
错误：

itemshop.c:48:14: error: expected expression
    itemshop(int buckaroonies);
             ^

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