C++ Integer Types signed and unsigned integers

#include <iostream>
using namespace std;
int main()/*from   w  ww  .  j a va 2 s . c om*/
{
   int signedVar = 1500000000;           //signed
   unsigned int unsignVar = 1500000000;  //unsigned
   signedVar = (signedVar * 2) / 3;  //calculation exceeds range
   unsignVar = (unsignVar * 2) / 3;  //calculation within range
   cout << "signedVar = " << signedVar << endl;  //wrong
   cout << "unsignVar = " << unsignVar << endl;  //OK
   return 0;
}