Illustration of else...if ladder

Program 17) An electric power distribution company charges its domestic consumers as follows:

Consumption Units       Rate of charge
   0 - 200                         Rs. 0.50 per unit
201 - 400                        Rs. 100 plus Rs. 0.65 per unit
                                      excess of 200
401 - 600                        Rs. 230 plus Rs. 0.80 per unit
                                      excess of 400
601 and above               Rs. 390 plus Rs. 1.00 per unit
                                      excess of 600

This program reads the customers number and power consumed and prints the amount to be paid by the customer.

                                    PROGRAM

main ( )
 {
       int units, cutnum ;
       float charges ;
       printf ("Enter CUSTOMER NO. and UNITS 
                                   consumed\n") ;
       scanf ("%d %d", &custom, &units) ;
       if (units <= 200)
           charges = 0.5 * units ;
       else if       (units <= 400)
                        charges = 100 + 0.65 * (units - 200) ;
                            else if (units <= 600)
                            charges = 230 + 0.8 * (units - 400) ;
                                else
                                 charges = 230 + 0.8 * (units - 400) ;
                                    else
                                    charges = 390 + (units - 600) ;
      printf ("\n\nCustomer No: %d: Charges = %2f\n",
                                           custnum, charges) ;
      getch( ) ;
 }

Output:     
     
Enter CUSTOMER NO.and UNITS consumed 101 150
Customer No: 101 Charges = 75.00

Enter CUSTOMER NO.and UNITS consumed 202 225
Customer No: 202 Charges = 116.25

Enter CUSTOMER NO.and UNITS consumed 303 375
Customer No: 303 Charges =  213.75


Enter CUSTOMER NO. and UNITS consumed 404 520
Customer No: 404 Charges = 326.00


Enter CUSTOMER NO. and UNITS consumed 505 625
Customer No: 505 Charges = 415.00