This is demo code for showing how a C program can be written using ncurses with certain level of generic code using function pointers. It is not a production quality app. It was built within a single day but still shows some good coding practices to a certain extent.

gcc main.c -o billing -lncurses
./billing

The folder where you run the executable should have a file named db.txt.
It needs to have entries in following manner:

<Item name, %s> <quantity, %d> <cost, %f>

where %s, %d and %f are scanf format specifiers. Ensure item name does not have spaces