Converting a double into date time

Question

I have a user input values in my table. Here if user enters 3.2, it mean 3 hours and 20 min.

I am showing the total hours that has been input by the user in the entire week.

Inputs are:
Sun : 3.2
Mon : 4.5
Tue: 5.0

Now, 3.2 + 4.5 + 5.0 = 12.70 which would mean 12 hours and 70 min. However, I want the result to be 13.10 (which is 13 hours and 10 min) instead of 12.70.

I need the total in a select query which is binding my grid with the rest of the data.

Currently i am using the sum function in the select query along with other columns.

How do I do this?

Answer 1

Your input format won't work at all.

You are lucky it does in your example but in most cases it just won't. For instance, if 2 persons input "1 hour and 50 minutes" :

1.5 + 1.5 = 3.0

You cannot read it as : "three hours" since in reality it is "3 hours and 40 minutes".

As soon as the sum of "minutes" is greater thant 0.99, your are wrong.

---

But in the few lucky cases, you can do some arithmetic (if you want a result in the same "double" format as your input)?

var inputList = new List<double>() {3.2, 4.5, 5.0};
double total = inputList.Sum();

int baseHours = (int)Math.Floor(total);
int realBaseHours = (int)inputList.Sum(d => Math.Floor(d));

if (baseHours > realBaseHours)
    throw new Exception("All hell breaks loose!");

int baseMinutes = (int)(total * 100.0 - baseHours * 100.0);

int finalHours = baseHours + baseMinutes / 60;
int finalMinutes = baseMinutes % 60;

double result = finalHours + finalMinutes / 100.0;

Answer 2

It's not good to saving times as a double format, but for your question:

Get all times as array of double values and do some arithmetic:

double[] times = { 3.2, 4.5, 5.0 };
int hours = 0;
int minuts = 0;
string[] values;
foreach (double t in times)
{
  values = t.ToString("#.00").Split('.');
  hours += int.Parse(values[0]);
  minuts += int.Parse(values[1]);
}
hours += minuts / 60;
minuts += minuts % 60;

It work for all kind of times as double format.