Total Tariff for different range of consumption in C program

1. Tariff Rs 1 per units for first 50 units
2. Tariff Rs 2 per units for next 100 units
3. Tariff Rs 3 per units for next 100 units
4. Tariff Rs 4 per units for more than 250 units

Sample output

Code is here

#include <stdio.h>
int main(void)
{
int slab1=0,slab2=0,slab3=0,slab4=0;
int rate1=1,rate2=2,rate3=3,rate4=4;
int units=0,total_tariff=0,final_tariff=0,surcharge=0;
printf("Enter the units consumed : ");
scanf("%d",&units);
if(units <= 50)	{
total_tariff= (units*rate1);
}else if(units <= 150  ){
total_tariff= (50*rate1) + ((units-50) * rate2);
}else if(units <=250 ){
total_tariff= (50*rate1) + (100 * rate2) + ((units-150) * rate3);
}else if(units >250){
total_tariff= (50*rate1) + (100 * rate2) + (100 * rate3) +
 ((units-250) * rate4);		
}

printf("Unit based tariff : %d \n",total_tariff);
if(units>150){
surcharge=	total_tariff*0.1;
printf("Surcharge %d \n",surcharge);
}else{
surcharge=0;	
printf("Surcharge 0 \n");	
}
final_tariff=total_tariff + surcharge;
printf("Bill Final %d : ",final_tariff);
return 0;
}