Compute the initial investment needed to attain a known future value given

   
 
/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/

/* Compute the initial investment needed to attain 
   a known future value given annual rate of return 
   and the time period in years. */ 
  
using System;  
  
public class IntialInvestment {     
  public static void Main() {     
    decimal InitInvest; // initial investment 
    decimal FutVal;     // future value 
 
    double NumYears;    // number of years  
    double IntRate;     // annual rate of return as a decimal 
  
    string str;  
 
    Console.Write("Enter future value: "); 
    str = Console.ReadLine(); 
    try {  
      FutVal = Decimal.Parse(str);  
    } catch(FormatException exc) {  
      Console.WriteLine(exc.Message);  
      return;  
    }  
 
    Console.Write("Enter interest rate (such as 0.085): "); 
    str = Console.ReadLine(); 
    try {  
      IntRate = Double.Parse(str);  
    } catch(FormatException exc) {  
      Console.WriteLine(exc.Message);  
      return;  
    }  
 
    Console.Write("Enter number of years: "); 
    str = Console.ReadLine(); 
    try {  
      NumYears = Double.Parse(str);  
    } catch(FormatException exc) {  
      Console.WriteLine(exc.Message);  
      return;  
    }  
 
    InitInvest = FutVal / (decimal) Math.Pow(IntRate+1.0, NumYears);  
  
    Console.WriteLine("Initial investment required: {0:C}", 
                      InitInvest);  
  }     
}