/***
write a prog reading info and print them
-use struct : item name, quantity, price, amount(price*quantity)
-function: read item from user, use ptr as prmter
-function: print items, use ptr as prmter
-int main(): 
    struct, ptr of struct, initialize both with NULL
    handle an error where mem alloc failed->terminate
    free
***/

#include <stdio.h>
#include <stdlib.h>

struct item
{
    char *itemName;
    int qty;
    float price;
    float amount;
};

void readItem(struct item *i);
void printItem(struct item *i);

int main()
{
    struct item itm = { NULL, 0, 0.0, 0.0 };
    struct item *pItem = NULL;

    pItem = &itm;

    pItem->itemName = (char *) malloc(30 * sizeof(char));

    if(pItem == NULL) //an error where mem alloc failed
        exit(-1); //terminate immediately

    // read item
    readItem(pItem);
    printf("\n\n OUTPUT \n");

    // print item
    printItem(pItem);

    free(pItem->itemName);

    return 0;
}

void readItem(struct item *i)
{
    printf("Enter product name: ");
    scanf("%s", i->itemName);

    printf("\nEnter price: ");
    scanf("%f", &i->price);

    printf("\nEnter quantity: ");
    scanf("%d", &i->qty);

    i->amount = i->qty * i->price;
}

void printItem(struct item *i)
{
    printf("\nName: %s",i->itemName);
    printf("\nPrice: %.2f",i->price);
    printf("\nQuantity: %d",i->qty);
    printf("\nTotal Amount: %.2f",i->amount);
}