Esempio n. 1
0
        static void Main(string[] args)
        {
            // non-generic version of collection
            Stack myStack = new Stack();

            myStack.Push("a string");
            myStack.Push(123);
            myStack.Push(3.3);
            myStack.Push(myStack);
            Console.WriteLine(myStack);

            //Console.WriteLine(myStack.Pop().GetType());
            //double aDobule = (double)myStack.Pop();

            //Console.WriteLine(myStack.Pop().GetType());
            //Console.WriteLine(myStack.Pop().GetType());
            //Console.WriteLine(myStack.Pop().GetType());

            // generic version of collections
            Stack <string> stringStack = new Stack <string>();

            stringStack.Push("a string");
            //stringStack.Push(123);
            string myStr = stringStack.Pop();

            var intStack = new Stack <int>();

            intStack.Push(123);
            //intStack.Push("a string");
            short aShort = 10;

            intStack.Push(aShort);
            long aLong = 100L;

            intStack.Push((int)aLong);

            GenericList <int> intList = new GenericList <int>();

            intList.AddHead(1);
            intList.AddHead(2);
            intList.AddHead(3);
            Console.WriteLine(intList);

            GenericList <string> strList = new GenericList <string>();

            strList.AddHead("Added First, Displayed Last!");
            strList.AddHead("Added Second, Displayed Second!");
            strList.AddHead("Added Last, Displayed First!");
            Console.WriteLine(strList);

            var doubleList = new GenericList <double>();

            doubleList.AddHead(1.1);
            doubleList.AddHead(2.2);
            doubleList.AddHead(3.3);
            Console.WriteLine(doubleList);

            foreach (var item in doubleList)
            {
                Console.WriteLine(item + " - ");
            }

            // value types:
            int intVal = 10;

            // reference types:
            object intValAsRefType = intVal;               // boxing
            int    anotherVal      = (int)intValAsRefType; // unboxing

            // type-safety
            //foreach (int item in myStack)
            //{
            //    Console.WriteLine(item);
            //}// end of foreach loop

            int x = 5;
            int y = 10;

            Swap(ref x, ref y);
            Console.WriteLine("x = " + x + ", y = " + y);
            double d1 = 2.2;
            double d2 = 5.5;

            Swap(ref d1, ref d2);
            Console.WriteLine("d1 = " + d1 + ", d2 = " + d2);
            string s1 = "first";
            string s2 = "second";

            Swap(ref s1, ref s2);
            Console.WriteLine("s1 = " + s1 + ", s2 = " + s2);

            GenericList <int> anotherList = new GenericList <int>();

            anotherList.AddHead(111);
            anotherList.AddHead(222);
            anotherList.AddHead(333);
            Swap(ref intList, ref anotherList);
            Console.WriteLine(intList);
            Console.WriteLine(anotherList);
        }// end of Main()
Esempio n. 2
0
        static void Main(string[] args)
        {
            // non-generic version of a collection
            Stack myStack = new Stack();

            myStack.Push("a string");
            myStack.Push(123);
            myStack.Push(3.3);
            //myStack.Push(myStack);
            Console.WriteLine(myStack.Peek());
            Console.WriteLine(myStack.Peek().GetType());
            double aDouble = (double)myStack.Pop(); //unboxing

            Console.WriteLine(aDouble + " unboxed");
            Console.WriteLine(myStack.Peek().GetType());
            //double aInt = (double)myStack.Pop(); //since the current item is an int. it will give a invalidCastException
            Console.WriteLine(myStack.Peek().GetType());

            // generic version of a collection
            Stack <string> stringStack = new Stack <string>();

            stringStack.Push("Apples");
            stringStack.Push("Grapes");
            //stringStack.Push(123); //compiler won't let you add different types (C#&Java are strongly typed)
            string myStr = stringStack.Pop(); // pop grapes

            Console.WriteLine(stringStack.Pop());

            var intStack = new Stack <int>();

            intStack.Push(123);
            //intStack.Push(3.3); // can't put double in intstack
            Console.WriteLine(intStack.Pop());
            short aShort = 10;

            intStack.Push(aShort); //implicit conversion from short to int happens
            long aLong = 10505050505050L;

            //intStack.Push(aLong); //implicit conversion doesn't work from long to int
            intStack.Push((int)aLong); // this works because you convert it first, but the
                                       // value might change when you cast long to int
            Console.WriteLine(intStack.Pop());


            GenericList <string> strList = new GenericList <string>();

            strList.AddHead("Apples");
            strList.AddHead("Grapes");
            strList.AddHead("Peaches");
            strList.AddHead("Pears");
            Console.WriteLine(strList);
            strList.AddFoot("Nectarines");
            strList.AddFoot("Raspberries");
            Console.WriteLine(strList);


            GenericList <int> intList = new GenericList <int>();

            intList.AddHead(5);
            intList.AddHead(2);
            intList.AddHead(9);
            intList.AddHead(4);
            Console.WriteLine(intList);
            intList.AddFoot(1);
            intList.AddFoot(8);
            Console.WriteLine(intList);

            var doubleList = new GenericList <double>();

            doubleList.AddHead(5.5);
            doubleList.AddHead(2.2);
            doubleList.AddHead(9.9);
            doubleList.AddHead(4.4);
            Console.WriteLine(doubleList);
            doubleList.AddFoot(1.8);
            doubleList.AddFoot(8.85);
            Console.WriteLine(doubleList);

            foreach (var item in strList)
            {
                Console.WriteLine(item + " -");
            }
            foreach (var item in intList)
            {
                Console.WriteLine(item + " -");
            }
            foreach (var item in doubleList)
            {
                Console.WriteLine(item + " -");
            }


            // value types:
            int intVal = 10;

            // reference types:
            object IntValAsRefType = intVal; //boxing

            int anotherVal = (int)IntValAsRefType;

            // you can only convert if you know what the type is otherwise it could act weird.
            Console.WriteLine(anotherVal);

            //All the collections store references to objects not the full objects themselves
            // so the stuff in nongeneric myStack above is being boxed as on object reference with each Push
            // this causes extra time.

            // Type-safety

            /*foreach (var item in myStack)
             * {
             *  Console.WriteLine(item);
             * } */

            int x = 5;
            int y = 10;

            Swap(ref x, ref y);
            Console.WriteLine("x=" + x + ", y=" + y);
            double d1 = 2.2;
            double d2 = 5.5;

            Swap(ref d1, ref d2);
            Console.WriteLine("d1=" + d1 + ", d2=" + d2);
            string s1 = "first";
            string s2 = "second";

            Swap(ref s1, ref s2);
            Console.WriteLine("s1=" + s1 + ", s2=" + s2);
            String st1 = "aaa";
            String st2 = "zzz";

            Swap(ref st1, ref st2);
            Console.WriteLine("st1=" + st1 + ", st2=" + st2);
            var anotherList = new GenericList <int>();

            anotherList.AddFoot(20);
            anotherList.AddHead(50);
            Console.WriteLine(intList);
            Console.WriteLine(anotherList);
            Swap(ref intList, ref anotherList); // types must be the same
            Console.WriteLine("s1=" + d1 + ", s2=" + d2);

            // simple arrays
            string[] fruits = { "Apple", "Orange", "Grapes" };
            Console.WriteLine(fruits[1]);
            fruits[2] = "Banana";
            int[] weights = new int[10];
            Console.WriteLine(weights[0]);

            string[,] sections = new string[3, 2];
            sections[0, 0]     = "top left";
            sections[0, 1]     = "top right";

            //List
            var fruitlist = new List <string>();

            fruitlist.Add("apple");
            fruitlist.Add("orange");
            fruitlist.Add("banana");
            Console.WriteLine(fruitlist);
            foreach (var item in fruitlist)
            {
                Console.WriteLine(item);
            }
            fruitlist.Sort();
            foreach (var item in fruitlist)
            {
                Console.WriteLine(item);
            }

            // Dictionary
            var inventory = new Dictionary <string, double>();

            inventory.Add("Apple", 19);
            inventory.Add("Orange", 49);
            inventory.Add("Banana", 57);

            var keys = inventory.Keys;

            foreach (var item in keys)
            {
                Console.WriteLine("Key: " + item);
                Console.WriteLine("Value: " + inventory[item]);
                // if key doesn't exist the line above will have an exception
            }

            double value;

            //Try to get the value of key 'watermelon' which doesn't exit
            if (inventory.TryGetValue("Watermelon", out value))
            {
                Console.WriteLine("Watermelon inventory: " + value);
            }
            else
            {
                Console.WriteLine("Watermelon not found in inventory");
            }

            if (inventory.TryGetValue("Apple", out value))
            {
                Console.WriteLine("Apples left: " + inventory["Apple"]);
                Console.WriteLine("Costumer bought 15 apples");
                inventory["Apple"] = value - 15; // person bought 19-4=15 apples 4 left
                Console.WriteLine("Apples left: " + inventory["Apple"]);
            }

            var prices = new Dictionary <string, double>();

            prices.Add("Apple", .79);
            prices.Add("Orange", 1.15);
            prices.Add("Banana", .54);
            // a better way would be to search both lists
            double totalBeforeTax = 0;

            if (prices.TryGetValue("Apple", out value))
            {
                Console.WriteLine("Apples cost: " + prices["Apple"]);
                Console.WriteLine("Costumer bought 15 apples");
                totalBeforeTax = prices["Apple"] * 15; // person bought 19-4=15 apples 4 left
                Console.WriteLine("Apples Total cost before tax: " + totalBeforeTax + "\n");
            }


            //sorted list
            var sortedList = new SortedList <string, string>();

            sortedList.Add("first", "David");
            sortedList.Add("second", "Smith");
            sortedList.Add("last", "Jack");

            var skeys = sortedList.Keys;

            foreach (var item in skeys)
            {
                Console.WriteLine("key = " + item + ", Value = " + sortedList[item]);
            }

            var days = new SortedList <int, string>();

            days.Add(1, "Sunday");
            days.Add(2, "Monday");
            days.Add(4, "Wednesday");
            days.Add(7, "Saturday");
            days.Add(6, "Friday");
            days.Add(3, "Tuesday");
            days.Add(5, "Thursday");

            var dkeys = days.Keys;

            foreach (var item in dkeys)
            {
                Console.WriteLine("Day: " + item + ", Value = " + days[item]);
            }

            sortedList.Remove("first");
        } // endof main