Question

int n;
        int[] ar = new int[50];
        Console.Write("Enter the size of array= ");
        n = int.Parse(Console.ReadLine());
        for (int i = 0; i < n; i++)
        {
            ar[i] = int.Parse(Console.ReadLine());
        }
        for (int i = 0; i < n; i++)
        {
            Console.WriteLine("AR["+i+"]="+ar[i]);
        }
        Console.Read();

As here you can see that when m entering the 09 or 08 its going to remove it and print the 9 and 8. And when same run on the c++ compiler then its print the 0 and 9 on different indices, why the compilers of both language doing behave like this? Why they do not reading it one digit?

Answer 1

The behavior of int.Parse(..) and other string to numeric parsing functions is to strip out any leading characters (zeros in this case) which are irrelevant to the numeric value.

If you wish to keep the leading zero then change the data type of your array to string.

Now that you’ve posted some code, here’s a few suggestions (comments inline)

    int n;
    bool validNumber;
    do {
      validNumber = true;
      Console.Write("Enter the size of array:");
      if(!int.TryParse(Console.ReadLine(), out n)) // use TryParse instead of Parse to avoid formatting exceptions
      {
          Console.WriteLine("Not a number, please try again");
          validNumber = false;
      }
    } while(!validNumber);  // re-prompt if an invalid number has been entered

    int[] ar = new int[n];    // declare the array after the size is entered - your code will break if the user enters a number greater than 50

    // change to "string[] ar = new string[n];" if you want to keep the full value entered

    for (int i = 0; i < n; i++)
    {
        bool valid;
        do {
          valid = true;
          int num;
          string value = Console.ReadLine();
          if(int.TryParse(value, out num))  // again - use tryparse.
            ar[i] = num;  // change to "ar[i] = value;" if you're using a string array. 
          else {
            Console.WriteLine("Please enter that again - not a number");
            valid = false;
          }
       } while(!valid);

    }
    for (int i = 0; i < n; i++)
    {
        Console.WriteLine("AR["+i+"]="+ar[i]);
    }
    Console.Read();