Please find an error in my noob program

The code works on another system, but when run on another computer (and possible an older compiler), the program either runs in an infinite loop or does not recognize the redirected input file.

Here is the code:

Code:

---

#include <stdio.h>

int main()
{

      int prod_num, number, counter=0, major_code=0, minor_code=0,
tax_code=0, where=0, total_number=0;
      double base_cost, minor_factor=0, shipping_costs=0, tax_amount=0,
final_unitprice=0,average_final, final_subtotal=0, final_price_product;

      while ( scanf("%d %lf %d", &prod_num, &base_cost, &number) != EOF)
      {
              total_number += number;
                          counter++;
              major_code = prod_num / 100000;
              minor_code = (prod_num % 100000) / 100;
              tax_code = (prod_num % 100) / 10;
              where = prod_num % 10;

              if(minor_code >= 0 && minor_code <= 399) {
                      minor_factor = 1.45;
              }

              else if ((minor_code>=400 && minor_code <=799) || (minor_code>=950
&& minor_code <=955)) {
                      minor_factor = 1.12;
              }

              else {
                      minor_factor = 0.89;
              }

              switch(where)
              {
                      case 0:        shipping_costs = 7.50;
                                              break;

                      case 1:        shipping_costs = 8.47;
                                              break;

                      case 2:        shipping_costs = 6.05;
                                              break;

                      case 3:        shipping_costs = 10.20;
                                              break;

                      default:        shipping_costs = 20.00;
                                              break;

              }

              if(tax_code == 1)

                      {

                      if(major_code>=0 && major_code<=250)
                              tax_amount = 0.12;

                      else if(major_code>=251 && major_code<=450)
                              tax_amount = 0.15;

                      else
                              tax_amount = 0.25;

                      }

              else if (tax_code == 0)
                      tax_amount = 0;

              final_unitprice = (base_cost * minor_factor + shipping_costs) * (1 + tax_amount);
              final_price_product = final_unitprice * number;
                          final_subtotal += final_price_product;
                         
              printf("---------------------------> PRODUCT [%d]<---------------------------\n", counter);
              printf("\n");
              printf("Product #: %d || Price/Unit: $%.2f || # of Products: %d ||
Total: $%.2f\n", prod_num, final_unitprice, number, final_price_product);
              printf("\n");
              printf("\n");

      }

average_final = final_subtotal / total_number;

                printf("\n");
                printf("The total price is: $%.2f\n", final_subtotal);
                printf("The average price per product is: $%.2f", average_final);
                printf("\n");
               
      return 0;
}

---

what operating system does the program not work on?

First,

Code:

---

              printf("Product #: %d || Price/Unit: $%.2f || # of Products: %d ||
Total: $%.2f\n", prod_num, final_unitprice, number, final_price_product);

---

don't wraps quoted strings this way. And avoid the line continuation thingy (which would be this):

Code:

---

              printf("Product #: %d || Price/Unit: $%.2f || # of Products: %d || \
Total: $%.2f\n", prod_num, final_unitprice, number, final_price_product);

---

Instead, make use of automatic concatenation of adjacent string literals:

Code:

---

      printf("Product #: %d || Price/Unit: $%.2f || # of Products: %d || "
            "Total: $%.2f\n", prod_num, final_unitprice, number, final_price_product);

---

Here

Code:

---

  while ( scanf("%d %lf %d", &prod_num, &base_cost, &number) != EOF )

---

it would be better to check for success rather than one potential failure:

Code:

---

  while ( scanf("%d %lf %d", &prod_num, &base_cost, &number) == 3 )

---

Can you post a sample input that causes the problem?