How to round a integer to the close hundred?

Question

I don\'t know it my nomenclature is correct! Anyway, these are the integer I have, for example :

76
121
9660

And I\'d like to round them to

Answer 1

I had a similar project internally where the business requirements were to search within the 100's range of a given number and find duplicate DB records. So if the user was using line 856 I would search 800 - 899. If the user was using 8567 I would search 8500 - 8599. Not an exact rounding by 100's, but thought I would include my unique approach as some of these basic coding questions are embedded within a larger business project. To test this I seeded a decimal list from 1 - 99999 and spit the results out into a file.

    /// 

    /// This method accepts an inbound Line Number and returns the line range
    /// in the form of lowest to highest based on 100's
    /// Example would be 9122 returns 9100 - 9199
    /// It's used for generating some additional BOM Temp functionality.
    /// 
    /// 
    /// 
    public static ProjectLineRange CalculateLineRange(decimal inboundNumber)
    {
        var lineRange = new ProjectLineRange();
        var numberLength = inboundNumber.ToString(CultureInfo.InvariantCulture).Length;

        switch (numberLength)
        {
            case 0: //NULL?
                break;
            case 1: //Represents 1 - 9
                lineRange.LineBottom = 1;
                lineRange.LineTop = 99;
                break;
            case 2: //Represents 10 - 99
                lineRange.LineBottom = 1;
                lineRange.LineTop = 99;
                break;
            case 3: //Represents 100 - 999
                lineRange = CalculateHundredsRange((int)(inboundNumber / 100));
                break;
            case 4: //Represents 1000 - 9999
                lineRange = CalculateThousandsRange(
                    Convert.ToInt32(inboundNumber.ToString(CultureInfo.InvariantCulture).Substring(1, 1)),
                    Convert.ToInt32(inboundNumber.ToString(CultureInfo.InvariantCulture).Substring(0, 1)));
                break;
            case 5: //Represents 10000 - 99999
                lineRange = CalculateTenThousandsRange(
                    Convert.ToInt32(inboundNumber.ToString(CultureInfo.InvariantCulture).Substring(2, 1)),
                    Convert.ToInt32(inboundNumber.ToString(CultureInfo.InvariantCulture).Substring(1, 1)),
                    Convert.ToInt32(inboundNumber.ToString(CultureInfo.InvariantCulture).Substring(0, 1)));
                break;
        }

        return lineRange;
    }

public class ProjectLineRange
    {
       public decimal LineBottom { get; set; }
       public decimal LineTop { get; set; }
    }

    /// 

    /// Helper method to return the range for the 100's place
    /// 
    /// 
    /// 
    public static ProjectLineRange CalculateHundredsRange(int hundredsPlaceValue)
    {
        var tempLineRange = new ProjectLineRange();
        tempLineRange.LineBottom = hundredsPlaceValue * 100;
        tempLineRange.LineTop = tempLineRange.LineBottom + 99;

        return tempLineRange;
    }

    /// 

    /// Helper method to return the range for the 100's place when factoring a 1000's number
    /// 
    /// 
    /// 
    /// 
    public static ProjectLineRange CalculateThousandsRange(int hundredsPlaceValue, int thousandsPlaceValue)
    {
        var tempLineRange = new ProjectLineRange();
        var tempThousands = thousandsPlaceValue * 1000;
        var hundredsRange = CalculateHundredsRange(hundredsPlaceValue);
        tempLineRange.LineBottom = tempThousands + hundredsRange.LineBottom;
        tempLineRange.LineTop = tempThousands + hundredsRange.LineTop;

        return tempLineRange;
    }

    /// 

    /// Helper method to return the range for the 100's place when factoring a 10000's number
    /// 
    /// 
    /// 
    /// 
    /// 
    public static ProjectLineRange CalculateTenThousandsRange(int hundredsPlaceValue, int thousandsPlaceValue, int tenThousandsPlaceValue)
    {
        var tempLineRange = new ProjectLineRange();
        var tempThousands = thousandsPlaceValue * 1000;
        var tempTenThousands = tenThousandsPlaceValue * 10000;
        var hundredsRange = CalculateHundredsRange(hundredsPlaceValue);
        tempLineRange.LineBottom = tempTenThousands + tempThousands + hundredsRange.LineBottom;
        tempLineRange.LineTop = tempTenThousands + tempThousands + hundredsRange.LineTop;

        return tempLineRange;
    }