code to calculate bill of things (gst 18% included)

#include<iostream>

using namespace std;

//code to calculate bill of 3 things

int main() {

    float pencil;

    float pen;

    float eraser;

    cout<<"enter pencil price: ";

    cin>>pencil;

    cout<<"enter pen price: ";

    cin>>pen;

    cout<<"enter eraser price: ";

    cin>>eraser;

    float bill = pencil+pen+eraser;

    float gst = bill*0.18;  // gst calculation

    float gstbill = bill+gst; // final bill after gst

    cout<<"total bill (before gst)= "<<bill<<endl;

    cout<<"total bill (after gst)= "<<gstbill<<endl;

    return 0;

}