c code for else if ladder

#include<stdio.h>
main()
 {
 int units,custnum;
 float charges;
 printf("Enter Customer NO. & Units consumed\n");
 scanf("%d%d",&custnum,&units);
 if(units<=200)
 charges=0.5*units;
 else if(units<=400)
 charges=100+0.65*(units-200);
 else if(units<=600)
 charges=230+0.40*(units-400);
 else
 charges=390+(units-600);
 printf("\n\nCustomer No:%d & Charges=%.2f\n",custnum,charges);
 }