using uCalcSoftware;

var uc = new uCalc();
var VariableX = uc.DefineVariable("x As Int32");
var MyStringVar = uc.DefineVariable("MyString = 'Hello world'");
var ParsedExpr = uc.Parse("SubStr(MyString, x, 1)");
var StrLength = uc.Eval("Length(MyString)");

for (int x = 0; x <= uc.Eval("Length(MyString) - 1"); x++) {
   VariableX.ValueInt32(x);
   Console.Write(ParsedExpr.EvaluateStr() + ".");
}