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