method metodaExemplu(x : int, y : int) returns (r : int)
{
  var z := x + y;
  return 17;
  r := 13;
  return;
  r := z;
}

method ex1()
{
  var r := metodaExemplu(13, 14);
  print r; // 17
}

method minMax(x : int, y : int) returns (min : int, max : int)
{
  if x < y {
    min := x;
    max := y;
  } else {
    min := y;
    max := x;
  }
}

/*
method fail1()
{
  var z := 0;
/*  if 3 > 4
    z := 13;
  else
    z := 14; */
   }
   */

method ex2()
{
  var min, max := minMax(18, 13);
//  print min, max; // 13, 18
}


method minMax1(x : int, y : int) returns (min : int, max : int)
  ensures min <= x <= max
  ensures min <= y <= max
  ensures min == x || min == y
  ensures max == x || max == y
{
  if x < y {
    min := x;
    max := y;
  } else {
    min := y;
    max := x;
  }
}

method minMax2(x : int, y : int) returns (min : int, max : int)
  ensures min <= x <= max
  ensures min <= y <= max
//  ensures min == x || min == y
//  ensures max == x || max == y
{
  if x < y {
    min := x;
    max := y;
  } else {
    min := y;
    max := x;
  }
}

method useMinMax()
{
  assert 1 < 3;
  // assert 3 < 1; // (fails)
  // assert forall x : int :: x < x + 13;
  
  var x, y := minMax(13, 18);
  // assert x <= y; (fails)
  var a, b := minMax1(13, 18);
  assert a <= b;
  assert a == 13;
  var u, v := minMax2(13, 18);
  assert u <= v;
  // assert u == 13; (fails)
}