using uCalcSoftware;

var uc = new uCalc();
var uc1 = new uCalc();
var uc2 = new uCalc();

var x1 = uc1.DefineVariable("x = 5");
var x2 = uc2.DefineVariable("x = 6");

Console.WriteLine(x1.uCalc.Eval("x*10")); // Same as uc1.Eval("x*10")
Console.WriteLine(x2.uCalc.Eval("x*10")); // Same as uc2.Eval("x*10")

uc1.Release();  // Since x1 is part of uc1, x1 is automatically released as well
uc2.Release();  // Since x2 is part of uc2, x2 is automatically released as well

// You should no longer use x1 or x2 because they were part of uc1 & uc2
// Don not try x1.uCalc().Eval("x*10"); or x2.uCalc().Eval("x*10");