Program C++ Rumus Bangun Ruang

#include<iostream>
#include<conio.h>
using namespace std;
    main(){
        int r,t,n;
        float phi,lingkaran,tabung,tabung1,kerucut;
        phi=3.14;
        cout<<"Nama      = Gontang Ragil Prakasa"<<endl;
        cout<<"Nim       = 1500018280 "<<endl;
        cout<<"Praktikum = Rabu, 13.30-15.00"<<endl;
        cout<<"Klik 1 (next) =";
        cin>>n;
        system("cls");
        cout<<endl;
        if(n==1){
       
        cout<<"=================================="<<endl;
        cout<<"     RUMUS BANGUN RUANG           "<<endl;
        cout<<"=================================="<<endl;
        cout<<"Masukkan jari jari ="; cin>>r;
        cout<<"Masukkan tinggi ="; cin>>t;
        cout<<"\n\n";
        lingkaran=phi*r*r;
        tabung= 2*phi*r*r + 2*phi*r*t ;
        tabung1=phi*r*t;
        kerucut=(1*phi*r*r*t)/3;
        cout<<"Luas Lingkaran"<<endl;
        cout<<"Rumus = phi*r*r"<<endl;
        cout<<"hasilya ="<<lingkaran;
        cout<<endl;
        cout<<endl;
        cout<<"Luas Tabung"<<endl;
        cout<<"Rumus = 2*phi*r*r + 2*phi*r*t"<<endl;
        cout<<"hasilya ="<<tabung;
        cout<<endl;
        cout<<endl;
        cout<<"Volume Tabung"<<endl;
        cout<<"Rumus = phi*r*t"<<endl;
        cout<<"hasilya ="<<tabung1;
        cout<<endl;
        cout<<endl;
        cout<<"Volume Kerucut"<<endl;
        cout<<"Rumus = 1/3*phi*r*r*t"<<endl;
        cout<<"hasilya ="<<kerucut;
        cout<<endl;
        cout<<endl;
        cout<<"\n\n";
        cout<<"                         Terima Kasih"<<endl;
    }
        getch();
}