calcuL

#include <iostream>
#include <cmath>
using namespace std;


int main()
{
  unsigned long x,a,b,e;

do {
      cout<<"1.adunare"<<endl;
      cout<<"2.scadere(in modul)"<<endl;
      cout<<"3.inmultire"<<endl;
      cout<<"4.impartire(doar catul)"<<endl;
      cout<<"5.exit"<<endl;
      cout<<"optiunea dvs e:"<<'\t';
      cin>>x;

      if (x!=5){
     cout<<"a=";cin>>a;
     cout<<"b=";cin>>b;
      }
     switch (x)
     {
         case 1:e=a+b;break;
         case 2:e=abs((double)a-(double)b);break;
         case 3:e=a*b;break;
         case 4:e=(a>b)?a/b:b/a;break;
         default : if (x!=5)
         cout<<"optiune invalida"<<endl;

     }
       if (x!=5)
     cout<<"E="<<e<<endl;
     else
        cout<<"mersi pt utilizare"<<endl;
  }  while (x!=5);

    return 0;
}