Thread: help with code

In my code when the customer is asked what they would like to purchase I need the code to show an error message if an item is selected that is not available in the menu could someone show me how I would implement this into my code

Code:

Code:

#include <stdio.h>


int isItemExists(char c, char itemPrefixes[]); 
void displayMenu(char itemPrefixes[], int prices[]); //function call including the arrays within the functions 
int getPrices(char c, char itemPrefixes[], int prices[]);
void getBudget();
int purchaseItem(char itemPrefixes[], int prices[]);
void thankYou();


int size;
int Budget = 0;
int RemainingBudget = 0;




int main()
{
    printf("--- ALL AVAILABLE FRUITS ---\n");
    printf("P: Pears\n");
    printf("M: Mango\n");
    printf("A: Apple\n");
    printf("O: Orange\n");
    printf("C: Cherry\n");
    printf("W: Watermelon\n");


    printf("-------------------------------------\n");


    printf("How many Fruits have you got in stock: ");
    scanf_s("%d", &size);


    int prices[8];
    char itemPrefixes[8]; //Declares the size of the arrays 
    int Choice = 0;
    while (Choice < size) {
        printf("\n(%d) Enter Fruit prefix:", Choice + 1);
        char prefix = ' ';
        scanf_s(" %c", &prefix, 1);
        if (isItemExists(prefix, itemPrefixes) == 1) { //Calls for the fucntion that Checks for duplication choice of items 
            printf("Error: Fruit already chosen!");
            continue;
        }
        else {
            itemPrefixes[Choice] = prefix;


            printf("Enter Price for (%c):", prefix);
            scanf_s("%d", &prices[Choice]);
            Choice++;
        }
    }


    displayMenu(itemPrefixes, prices);
    getBudget(); 


        char run = 'y';
    while (run == 'y') {
        char choice;
        printf("\nSHOP OPERATIONS\n");
        printf("1. Enter 'c' to check if Fruit is in stock\n");
        printf("2. Enter 'd' to display Menu\n");
        printf("3. Enter 'm' to display item prices\n"); //Displays the options of the shops to the customers 
        printf("4. Enter 'i' to compare budget with item prices\n");
        printf("5. Enter 'p' to purchase an item\n");
        printf("Enter your choice: ");


        scanf_s(" %c", &choice, 1);


        char cSearch;
        if (choice == 'c') {
            printf("Please enter Fruit prefix to search: \n");
            scanf_s(" %c", &cSearch, 1);
            int found = isItemExists(cSearch, itemPrefixes);


            if (found) {
                printf("Fruit FOUND!");
            }
            else {
                printf("Fruit NOT FOUND!");
            }
        }
        else if (choice == 'd') {


            displayMenu(itemPrefixes, prices);


        }
        else if (choice == 'm') {
            printf("Please enter fruit prefix: \n");
            scanf_s(" %c", &cSearch, 1);
            int m = getPrices(cSearch, itemPrefixes, prices);
            if (m > 0) {
                printf("The price of %c is %d\n", cSearch, m);
            }
            else {
                printf("%c has not been selected!", cSearch);
            }


        }
        else if (choice == 'i') {
            printf("Your avalible budget is %d\n", Budget);
            printf("Please enter an item you would like to compare your budget with: \n");
            scanf_s(" %c", &cSearch, 1);
            int i = getPrices(cSearch, itemPrefixes, prices);
            if (i <= Budget) {
                printf("You have sufficiant budget to purchase this fruit\n");
                RemainingBudget = Budget - i;
                printf("Remaining budget is: %d\n", RemainingBudget);
            }
            else {
                printf("You do not have enough funds to purchase this item, Please add funds");
            }
        }
        else if (choice == 'p') {
            printf("Please enter what item you would like to purchase from the Menu: ");
            scanf_s(" %c", &cSearch, 1);
            displayMenu(itemPrefixes, prices);
            int p = purchaseItem(cSearch, itemPrefixes, prices); // Option P is how the customers makes the purchase and receievs recipt 
            if (p > Budget) {
                printf("You have insuffciant funds for this item\n");
            }
            else if (p <= Budget); {
                int o = getPrices(cSearch, itemPrefixes, prices);
                RemainingBudget = Budget - o;
                printf("Item selected: %c\n", cSearch);
                printf("Item price : %d\n", o);
                printf("Remaining budget:%d\n", RemainingBudget);
            }
        }
        else {
            printf("Please enter a valid choice!");
        }


        printf("\nDo you want to keep shopping: (y/n)?");


        scanf_s(" %c", &run, 1);
    }
    thankYou(); // function exits program when n is selected 
    return 0;
}


void getBudget() {
    printf("**************************************\n");
    printf("Hello and welcome to my fruit shop\n"); // function Initlization for the customer to enter their budget
    printf("Please enter your budget : ");
    scanf_s(" %d", &Budget);
}
int isItemExists(char prefix, char itemPrefixes[]) {
    for (int i = 0; i < size; i++) {
        if (itemPrefixes[i] == prefix) { //function uses arrays to see whether item has been chosen twice
            return 1;
        }
    }
    return 0;
}


void displayMenu(char itemPrefixes[], int prices[]) {
    printf("\n***** SHOP MENU *****\n");
    printf("Fruit:\tPrices");
    for (int i = 0; i < size; i++) {
        printf("\n%c:\t%d", itemPrefixes[i], prices[i]); // fucntion displays menu 
    }
    printf("\n\n"); 
}
int purchaseItem(char itemPrefixes[], int prices[]) {
    printf("Your purchase has been successful!\n"); // function gives the recipt to the customer
    printf("Purchase details\n");
    printf("---------------------------------\n");
    return 0;
}


int getPrices(char c, char itemPrefixes[], int prices[]) {
    for (int i = 0; i < size; i++) {
        if (c == itemPrefixes[i]) {
            return prices[i];  //get prices of the items
        }
    }
    return -1;
}
void thankYou() {
    printf("Thanks for shopping with us!\n"); // Function intlization for thank you message and to exit program
    exit(0);
}