fungsi tabung

#include <iostream>
#include <math.h>

using namespace std;

float lstabung(int r, int t);
float vtabung(int r, int t);
void garis();

main(){
    system ("color 70");
    int jari, tinggi, pil;

    cout << "Penghitung Luas Permukaan dan Volume Tabung"<<endl;
    garis();
    cout << "Inputkan Jari-Jari : "; cin >> jari;
    cout << "Inputkan Tinggi    : "; cin >> tinggi;
    cout << "1. Luas Selimut Tabung"<<endl<<"2. Volume Tabung"<<endl;
    cout << "Inputkan Pilihan   : "; cin >> pil;
    garis();
    switch (pil) {
        case 1 : {
            cout << "Rumus = 2*phi*r*(t+r)"<<endl;
            cout << "2 * 3.14 * "<< jari <<" * "<<"("<< tinggi <<"+"<< jari << ")"<< lstabung(jari,tinggi);
            break;
        }
        case 2 : {
            cout << "Rumus = phi*r^2*t"<<endl;
            cout << "4.14 * " <<jari<<"^2 * "<<tinggi<<" = "<<vtabung(jari,tinggi);
            break;
        }
    }
    cin.get();
}

void garis(){
    cout << "==========================================="<<endl;
}
float lstabung(int r, int t){
    float phi=3.14,hasil;
    hasil = 2*phi*r*(t+r);
    return hasil;
}

float vtabung(int r, int t){
    float phi=3.14, hasil;
    hasil = phi*pow(r,2)*t;
    return hasil;
}