menghitung luas bangun datar dengan case dalam bahasa c++

#include <stdio.h>
#include <conio.h>
#include <iostream.h>
#include <math.h>
main ()
{
 int bangun,ulangi;
 ulangi:
 clrscr ();
 cout<<"\t\tPROGRAM HITUNG LUAS BANGUN DATAR"<<endl;
 cout<<"\t================================================\n"<<endl;
 cout<<"\t(1) Persegi\n";
 cout<<"\t(2) Persegi Panjang\n";
 cout<<"\t(3) Segitiga\n";
 cout<<"\t(4) Jajar Genjang\n";
 cout<<"\t(5) Trapesium\n";
 cout<<"\t(6) Layang-layang\n";
 cout<<"\t(7) Belah Ketupat\n";
 cout<<"\t(8) Lingkaran\n";
 cout<<"\n\tPilih Bangun Datar : ";cin>>bangun;
 cout<<"\t================================================\n"<<endl;
 cout<<endl;
 if(bangun==1)
  {
   int sBS,Lbujursangkar;
   cout<<"\t\tMenghitung Luas Persegi\n";
   cout<<"\t================================================\n"<<endl;
   cout<<"\tMasukkan Nilai Sisi = "; cin>>sBS;
   Lbujursangkar=sBS*sBS;
   cout<<"\n\tLuas Persegi\t= "<<Lbujursangkar<<endl;
   getch ();
   cout<<"\n\tAnda Ingin Mengulangi lagi? [Y/T] = ";
   ulangi = getche();
if(ulangi == 'Y' || ulangi == 'y')
    goto ulangi;
   else
   if(ulangi == 'T' || ulangi == 't')
    {
cout<<"\n\n\tTerima Kasih";
      getch ();
      }
  }
  else
  if (bangun==2)
  {
   int pPP,lPP,LPersegiPanjang;
   cout<<"\t\tMenghitung Luas Persegi Panjang\n";
   cout<<"\t================================================\n"<<endl;
   cout<<"\tMasukkan Nilai Panjang = "; cin>>pPP;
   cout<<"\tMasukkan Nilai Lebar = "; cin>>lPP;
   LPersegiPanjang=pPP*lPP;
   cout<<"\n\tLuas Persegi Panjang\t= "<<LPersegiPanjang<<endl;
   getch ();
   cout<<"\n\tAnda Ingin Mengulangi lagi? [Y/T] = ";
   ulangi = getche();
if(ulangi == 'Y' || ulangi == 'y')
    goto ulangi;
   else
   if(ulangi == 'T' || ulangi == 't')
    {
cout<<"\n\n\tTerima Kasih";
      getch ();
      }
  }
  else
  if (bangun==3)
  {
   int a,t,Lsegitiga;
   cout<<"\t\tMenghitung Luas Segitiga\n";
   cout<<"\t================================================\n"<<endl;
   cout<<"\tMasukkan Nilai Alas = "; cin>>a;
   cout<<"\tMasukkan Nilai Tinggi = "; cin>>t;
   Lsegitiga=(a*t)/2;
   cout<<"\n\tLuas Segitiga \t= "<<Lsegitiga<<endl;
   getch ();
   cout<<"\n\tAnda Ingin Mengulangi lagi? [Y/T] = ";
   ulangi = getche();
if(ulangi == 'Y' || ulangi == 'y')
    goto ulangi;
   else
   if(ulangi == 'T' || ulangi == 't')
    {
cout<<"\n\n\tTerima Kasih";
      getch ();
      }
  }
  else
  if (bangun==4)
  {
   int aj,tj,Ljar;
   cout<<"\t\tMenghitung Jajar Genjang\n";
   cout<<"\t================================================\n"<<endl;
   cout<<"\tMasukkan Nilai Alas = "; cin>>aj;
   cout<<"\tMasukkan Nilai Tinggi = "; cin>>tj;
   Ljar=aj*tj;
   cout<<"\n\tLuas Jajar Genjang \t= "<<Ljar<<endl;
   getch ();
   cout<<"\n\tAnda Ingin Mengulangi lagi? [Y/T] = ";
   ulangi = getche();
if(ulangi == 'Y' || ulangi == 'y')
    goto ulangi;
   else
   if(ulangi == 'T' || ulangi == 't')
    {
cout<<"\n\nTerima Kasih";
      getch ();
      }
  }
  else
  if (bangun==5)
  {
   int s1t,s2t,ttap,Ltrap;
   cout<<"\t================================================\n"<<endl;;
   cout<<"\t\t========================\n\n";
   cout<<"\tMasukkan Nilai Sisi 1 = "; cin>>s1t;
   cout<<"\tMasukkan Nilai Sisi 2 = "; cin>>s2t;
   cout<<"\tMasukkan Nilai Tinggi = "; cin>>ttap;
   Ltrap=((s1t+s2t)*ttap)/2;
   cout<<"\n\tLuas Trapesium \t= "<<Ltrap<<endl;
   getch ();
   cout<<"\n\tAnda Ingin Mengulangi lagi? [Y/T] = ";
   ulangi = getche();
if(ulangi == 'Y' || ulangi == 'y')
    goto ulangi;
   else
   if(ulangi == 'T' || ulangi == 't')
    {
cout<<"\n\n\tTerima Kasih";
      getch ();
      }
  }
  else
  if (bangun==6)
  {
   int d2l,d1l,Llay;
   cout<<"\t\tMenghitung Luas Layang-layang\n";
   cout<<"\t================================================\n"<<endl;
   cout<<"\tMasukkan Nilai Diagonal 1 = "; cin>>d1l;
   cout<<"\tMasukkan Nilai Diagonal 2 = "; cin>>d2l;
   Llay=(d1l*d2l)/2;
   cout<<"\n\tLuas Layang-layang \t= "<<Llay<<endl;
   getch ();
   cout<<"\n\tAnda Ingin Mengulangi lagi? [Y/T] = ";
   ulangi = getche();
if(ulangi == 'Y' || ulangi == 'y')
    goto ulangi;
   else
   if(ulangi == 'T' || ulangi == 't')
    {
cout<<"\n\n\tTerima Kasih";
      getch ();
      }
  }
  else
  if (bangun==7)
  {
   int dbk2,dbk1,Lbk;
   cout<<"\t\tMenghitung Belah Ketupat\n";
   cout<<"\t================================================\n"<<endl;
   cout<<"\tMasukkan Nilai Diagonal 1 = "; cin>>dbk1;
   cout<<"\tMasukkan Nilai Diagonal 2 = "; cin>>dbk2;
   Lbk=(dbk1*dbk2)/2;
   cout<<"\n\tLuas Segitiga \t= "<<Lbk<<endl;
   getch ();
   cout<<"\n\tAnda Ingin Mengulangi lagi? [Y/T] = ";
   ulangi = getche();
if(ulangi == 'Y' || ulangi == 'y')
    goto ulangi;
   else
   if(ulangi == 'T' || ulangi == 't')
    {
cout<<"\n\n\tTerima Kasih";
      getch ();
      }
  }
  else
  if(bangun==8)
  {
   float jari,Lkaran;
   cout<<"\t\tMenghitung Luas Lingkaran\n";
   cout<<"\t================================================\n"<<endl;
   cout<<"\tMasukkan Nilai Jari-jari = "; cin>>jari;
   Lkaran=(jari*jari)*22/7;
   cout<<"\n\tLuas Lingkaran = "<<Lkaran<<endl;
   getch ();
   cout<<"\n\tAnda Ingin Mengulangi lagi? [Y/T] = ";
   ulangi = getche();
if(ulangi == 'Y' || ulangi == 'y')
    goto ulangi;
   else
   if(ulangi == 'T' || ulangi == 't')
    {
cout<<"\n\n\tTerima Kasih";
      getch ();
      }
   }
   else
   if(bangun>8)
   {
    cout<<"\tAnda Salah Memasukkan Angka,"<<endl ;
    cout<<"\tTekan Enter Untuk Melanjutkan..."<<endl;
    getch ();
    cout<<"\n\tAnda Ingin Mengulangi lagi? [Y/T] = ";
    ulangi = getche();
if(ulangi == 'Y' || ulangi == 'y')
    goto ulangi;
      else
      if(ulangi == 'T' || ulangi == 't')
    {
cout<<"\n\n\tTerima Kasih";
      getch ();
      }
   }
}