Store Front C Program

[ccomputer]

Hayy everyone,
Since I am such a newbie to C programing, I was wondering if someone can help me. I want to write a program that simulate the front of a store operations common today. I want my program to look up the price and taxability of the item, computes the tax, keeps a running total, deducts from inventory the sale of the item, and finally prints out the receipt for the customer. Here is what I have now.

#include "stdio.h"
#include "stdlib.h
#define	FILENAME			"db.txt"
#define	RECEIPT_FILE	"receipt.txt"
#define	TAXRATE			0.065


int Lookup_Item_Quantity(FILE *db, int item);
double Lookup_Item_Price(FILE *db, int item);
char Lookup_Item_Taxability(FILE *db, int item);
double Compute_Tax(FILE *db, int item, int qty);
int Remove_Qty_From_Inventory(FILE *db, int item, int qty);
int Create_Receipt(FILE *db, int items[][2], int itemcnt);

main() {
int Q;
double price;
char tax;
double O;
double T;
double N;
    
    FILE*db;
    db=fopen("db.txt", "r+");
    Q=Lookup_Item_Quantity(db, 333333);
    printf("%i", Q);
    
    FILE*db;
    db=fopen("db.txt", "r+");
    Price=Lookup_Item_Price(db, 333333);
    printf("%lf", price);
    
    FILE*db;
    db=fopen("db.txt","r+");
    tax=Lookup_Item_Taxability(db, 333333);
    printf("%c", tax);
    
    FILE*db;
    db=fopen("db.txt", "r+");
    ComputeT=Compute_Tax(db, 33333);
    printf("%i", "%lf", Q,Item);
	
	
	
} // end of main()

int Remove_Qty_From_Inventory(FILE *db, int item, int qty){

	int		rval=1;
	FILE		*db2 = fopen("temp.txt", "w");


	// ...
	// YOUR CODE GOES HERE...
	// Copy everything over from the db.txt file
	//  over to the temp.txt file -- be sure to
	//  subtract qty from the proper item
	// ...
	
	

	// This code renames the temporary file	
	// to be the new database file
	fclose(db);
	fclose(db2);
	remove(FILENAME);
	rename("temp.txt", FILENAME);
	db = fopen(FILENAME, "r+");
	
	
	return rval;
	
} // end of Remove_Qty_From_Inventory()

rewind();
int Lookup_Item_Quantity(FILE *db, int item){
    while (in !=item){
        fscanf(db, "%i", &in);
        fscanf(db,"%lf\n" &price);
        fscanf(db, "%c", &tax);
        fscanf(db, "%i", &Q);
    }//end of while
    return Q;
	
} // end of Lookup_Item_Quantity()

rewind();
double Lookup_Item_Price(FILE *db, int item){
    while (in !=item){
        fscanf(db, "%i", &in);
        fscanf(db,"%lf\n" &price);
        fscanf(db, "%c", &tax);
        fscanf(db, "%i", &Q);
    }//end of while
    return price;
	
} // end of Lookup_Item_Price()

rewind();
char Lookup_Item_Taxability(FILE *db, int item){
    while (in !=item){
        fscanf(db, "%i", &in);
        fscanf(db,"%lf\n" &price);
        fscanf(db, "%c", &tax);
        fscanf(db, "%i", &Q);
    }//end of while
    return tax;
	
} // end of Lookup_Item_Taxability()

rewind();
double Compute_Tax(FILE *db, int item, int qty){
    switch(tax, Q){
        case 'O'(if O!= .99999);
        case 'T'(if T!=.06);
        case 'N'(if N!= .07);
    }//end of switchcase
        
	
} // end of Compute_Tax()

int Create_Receipt(FILE *db, int items[][2], int itemcnt){
	
} // end of Create_Receipt()

Thanks for the help!

[Sebastiani]

...and your question is?

[dwks]

You can't have function calls (eg, rewind()) outside of functions.

    switch(tax, Q){
        case 'O'(if O!= .99999);
        case 'T'(if T!=.06);
        case 'N'(if N!= .07);
    }

You should definitely read up on how a switch works. It takes an integral expression, not "tax, Q":

    switch(input) {
    case '1':
        load_file();
        break;
    case '2':
        write_file();
        break;
    }

And Q is a variable local to main(), which is not visible (in scope) in Compute_Tax(). Make it a global variable or pass it into the function if you want to use it.

As for this . . .

	// ...
	// YOUR CODE GOES HERE...
	// Copy everything over from the db.txt file
	//  over to the temp.txt file -- be sure to
	//  subtract qty from the proper item
	// ...

Look up getc().