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nagarjuna02
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Substring outofindex

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I wrote a code for which

if 23E+20 is the input then output should be 230000000(20 zeros)

if 4.456E-14 is the input then 4.456000(14 zeros) should be the output

But its not working properly. Please let me know where I did error. Thank You.
using System;

class test

{

public static void Main()

{

Console.WriteLine("Enter double");

String ext =Console.ReadLine();



if(ext.IndexOf("E")!=-1)
{
int i=ext.IndexOf("E");

ext = ext.Substring(0, i);

for (int j = 0; j < int.Parse(ext.Substring(i + 1, ext.Length - (i + 1))); j++)

ext = ext + "0";

Console.WriteLine(ext);



}

}

c# strings
  • asked one year ago
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last answered one year ago

2 answers

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i don't know if 4.456E-14 is right coz it should be in the left but here is the code.

Console.WriteLine("Enter double");

            String ext =Console.ReadLine();
            int i=ext.IndexOf("E");
            if (i != -1)
            {
                i++;
                int exp = Math.Abs(int.Parse(ext.Substring(i, ext.Length - i)));
                ext = ext.Substring(0, i-1);
                for (int j = 0; j < exp; j++)
                    ext += "0";
            }

            Console.WriteLine(ext);
            Console.Read();

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This problem is more difficult than it looks.

Whilst muster's solution deals OK with integer mantissas with non-negative exponents, it doesn't deal with negative exponents and also doesn't deal with non-integral mantissas such as 4.456E-14.

The following does deal with them as long as you don't need more than 99 digits after the decimal point, if there is one. Rather than generating the additional zeros 'manually', it makes use of .NET's standard numeric format "F":

using System;

class Test
{
   public static void Main()
   {

      Console.WriteLine("Enter q to quit at any time\n");
      
      while(true)
      { 
         Console.Write("Enter double : ");
         string ext = Console.ReadLine().ToUpper(); // deals with 'e' as well
         if (ext == "Q") return;

         // make sure it's a valid double first
         double d;

         if(!double.TryParse(ext, out d))
         {
            Console.WriteLine("Not a valid double\n");
            continue;
         }

         // get index of E if there is one  
         int i = ext.IndexOf("E"); 

         if (i != -1)
         {
           char op = ext[i + 1]; // '+' or '-' or first digit
           int pow;

           if (op != '+' && op != '-')
           {
              pow = int.Parse(ext.Substring(i + 1));
           }
           else
           {
              pow = int.Parse(ext.Substring(i + 2));
              if (op == '-') pow = -pow;
           }

           int dp = ext.IndexOf("."); // get index of decimal point, if any
          
           if (dp == -1) dp = i; // if no dp, put an imaginary one where E is
           
           int np = i - dp - pow; // decimal places, if any, to show for number
           if (np < 0) np = 0; // can't be less than zero
           if (np < 100) // can't deal with precision above F99
           {                        
               ext = d.ToString("F" + np.ToString());
               if (np > 0) ext = ext.TrimEnd('0').TrimEnd('.'); // tidy up string  
           }
         } 
         Console.WriteLine("Result is    : {0}\n", ext);                     
      }
   }
}

  • answered one year ago by:

    vulpes
    17279
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