static void Main() { ExpressionTree exp = new ExpressionTree(); DataService dataService = new DataService(); Node Tree = exp.BuildTree(dataService.Expression); //or exp.BuildTree("your expression"), like exp.BuildTree("(1+2*3)") WriteLine("Expression is : " + dataService.Expression); Write("Preorder traversal (KLP) is : "); exp.PreOrder(Tree); Write("\nInorder traversal (LKP) is : "); exp.InOrder(Tree); Write("\nPostorder traversal (LPK) is : "); exp.PostOrder(Tree); WriteLine("\nThe result of the calculation is : " + exp.Calculate(Tree)); WriteLine("Tree height is : " + exp.Height(Tree)); }