3.Write a program to find out the how many 9 is present in given input eg:100 to 10000 ?

--Loop this function for every number from 100 to 10000 static void ConvertToInt(Int32 iNum, int iNoToFind,ref int iCnt) { Int32 iDig = Convert.ToInt32(Math.Floor(Math.Log10(iNum))); Int32 iDiv =Convert.ToInt32(Math.Pow(10, iDig)); if(iNum/iDiv ==iNoToFind) { iCnt++; } if(iNum/10 > 0 && iNum%iDiv > 0) ConvertToInt( iNum%iDiv, iNoToFind, ref iCnt); }

--looped in SQL, can be done similarly in c# as well declare @min int = 0,@max int=100,@ctr int =0,@nines int = 0,@str nvarchar(10)='' while (@min<=@max) Begin set @str = convert(nvarchar(10),@min) set @nines = @nines + (len(@str)-len(replace(@str,'9',''))) set @min=@min+1 End select @nines

public static void Main() { int a = 100; int b = 10000; int count = 0; int c = 0; int x = 0; for (int i = a; i <= b; i++) { c = i; while (c != 0) { x = c % 10; c = c / 10; if (x == 9) { count++; } } } Console.WriteLine(count); }

public static void Main() { int a = 100; int b = 10000; int count = 0; int c = 0; int x = 0; for (int i = a; i <= b; i++) { c = i; while (c != 0) { x = c % 10; c = c / 10; if (x == 9) { count++; } } } Console.WriteLine(count); }