using uCalcSoftware;

var uc = new uCalc();
var myVar = uc.DefineVariable("x");
var expr = uc.Parse("x * 2");

var i = 0;
for ( i = 1; i <= 5; i++) {
   myVar.Value(i);
   Console.WriteLine($"When x is {i}, result is: {expr.Evaluate()}");
}