icp/oer/courses/c-newcomers/sections/04-supermarket/04-customer/content.md

You prepared the cashier for the step to multiple cashiers. But let's not go there yet. First you should flesh out the concept of a customer.

Model

In our model the customer should have a list of items he buys, but you could add more things to make it more interesting. For example some customers pack their items painfully slow and some really fast. So let's add that too. So the scanning phase takes the amount of time of the item plus the packing-speed.

Knowledge

For that we need a new language construct. The struct. A struct works similar to an enum, but instead counting up numbers, you basically packing multiple variables together to build more complex data-types.

Here is an example of a struct for a person:

typedef struct
{
    char *Name;    // This is some Text
    int Age;

    gender Gender; // This is an enum
}person;

If you want to access a member of the struct you write first the name of the variable containing the struct, then a dot and then the name of the member. For example we have a variable Bob person Bob and want to assign him an age of 35 Bob.age = 35.

Because the file got a little big, we pulled out some of the definitions like the enums into a header file and included it with the command #include "supermarket.h".

Task

Your task is to implement a struct for the customer and take the packing speed into account.