Electricity bill

//  Electricity bill
//  Date : 20.10.19
#include<iostream>
using namespace std;

int main(){
    cout << "Enter the used electric unit: ";
    int unit; cin >> unit;
    double bill = 0;
    if(unit > 250){
        bill = (50 * 0.50) + (100 * 0.75) + (100 * 1.20) + ((unit - 250) * 1.50);
    }
    else if(unit > 150){
        bill = (50 * 0.5) + (100 * 0.75) + ((unit - 150) * 1.20);
    }
    else if( unit > 50){
        bill = (50 * 0.5) + ((unit - 50) * 0.75);
    }
    else bill = unit * 0.5;

    bill = bill + ((20 * bill) / 100);

    cout << bill;
}