Question

Instead of using int.TryParse, use int.Parse instead and use try/catch in C# to handle possible errors

using System;
using System.Collections.Generic;
                  
public class Program
{
   public static void Main()
   {
       List<int> list = new List<int>();
      
       Console.WriteLine("Please input integers: (in one line)");
      
      
       string input = Console.ReadLine();
       string[] tokens = input.Split(); // split string into tokens "12 13 10" -> "12" "13" "10"
      
       foreach (string s in tokens) {
           int num;
           bool success = int.TryParse(s,out num); // TryParse returns true if successfully converted s into an int
                   // the converted int is put into the second parameter using keyword "out"  
           // do you know why "out" is used here? why not return the converted integer?
           if (success) {
               list.Add(num); // add num to list if success
           }
       }
      
       Console.WriteLine("Sorted input:");
       list.Sort();
       foreach(int i in list) {
           Console.WriteLine(i);
       }
       Console.WriteLine("Sorted input in reverse:");
       for (int i=list.Count-1;i>=0;i--) {
           Console.WriteLine(list[i]);
       }
      
   }
}

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

//MODIFIED CODE.

using System;

using System.Collections.Generic;

public class Program {

                public static void Main() {

                                List < int > list = new List < int > ();

                                Console.WriteLine("Please input integers: (in one line)");

                                string input = Console.ReadLine();

                                string[] tokens = input.Split(); // split string into tokens "12 13 10" -> "12" "13" "10"

                                foreach(string s in tokens) {

                                               int num;

                                               //opening try block

                                               try {

                                                               //parsing s as integer, will cause exception if s is not int

                                                               num = int.Parse(s);

                                                               //if no exceptions occurred, simply adding num to list

                                                               list.Add(num);

                                               } catch(Exception e) {

                                                               //exception occurred, ignoring current token

                                               }

                                }

                                Console.WriteLine("Sorted input:");

                                list.Sort();

                                foreach(int i in list) {

                                               Console.WriteLine(i);

                                }

                                Console.WriteLine("Sorted input in reverse:");

                                for (int i = list.Count - 1; i >= 0; i--) {

                                               Console.WriteLine(list[i]);

                                }

                               

                }

}

/*OUTPUT*/

Please input integers: (in one line)

a b c 11 -2 3 s 4 -99 100 xyz 7

Sorted input:

-99

-2

3

4

7

11

100

Sorted input in reverse:

100

11

7

4

3

-2

-99