Insert object into string

Question

I wanted to create a readonly struct that represents time in 24-hour format, so it has a method that is supposed to return a string of time (for example: "08:45" if 8 and 45 were passed respectively or "03:40" if 25 hours and 160 minutes were passed)

The problem is in the method, how do I return a string with values from the object inserted into it? I imagined something like return "0{stringtimeobj.hours}:0{stringtimeobj.minutes} but I can't really figure out how to format a string so that it has values from an object in it. Please help out!

using System;

namespace TimeStruct
{
    public readonly struct Time
{
        private readonly int hours2;
        private readonly int minutes2;

        public Time(int minutes)
            : this()
        {
            this.minutes2 = minutes;
        }

        public Time(int hours, int minutes)
        {
            this.hours2 = hours;
            this.minutes2 = minutes;
            }

        public int Hours
        {
            get
            {
                if (this.hours2 < 24)
                {
                    return this.minutes2;
                }
                else if (this.hours2 == 24)
                {
                    return 0;
                }
                else
                {
                    double overflowtohours = ((Math.Truncate((double)this.minutes2 / 60) + 1) * 60) - 60;
                    return Convert.ToInt32(this.hours2 - ((Math.Truncate((double)(Convert.ToInt32(overflowtohours / 60) + this.hours2) / 24) + 1) * 24) - 24);
                }
            }
        }

        public int Minutes
        {
            get
            {
                if (this.minutes2 < 60)
                {
                    return this.minutes2;
                }
                else if (this.minutes2 == 60)
                {
                    return 0;
                }
                else
                {
                    double overflowtohours = ((Math.Truncate((double)this.minutes2 / 60) + 1) * 60) - 60;
                    return Convert.ToInt32(this.minutes2 - overflowtohours); 
                }
            }
        }

        public string ToString(int hours3, int minutes3)
        {
            Time stringtimeobj = new Time(hours3, minutes3);
            return /* string "00:00" with hour and minute values from object stringtimeobj inserted */
        }
    }
}

Why is your ToString parameterized? Normally you'd have a parameterless method that uses the data in the object you're calling it on. — Jon Skeet
– Jon Skeet, Commented Jul 17, 2022 at 14:59
Tip: someInt. ToString("00") will add leading zero as needed — Hans Keﬆing
– Hans Keﬆing, Commented Jul 17, 2022 at 15:19
@JonSkeet I thought that method needed to be passed parameters, then these parameters are used in the constructor when new object is created, does that make sense? I can't really think of another way to implement the method — Akzhol
– Akzhol, Commented Jul 17, 2022 at 17:44
No, it's an instance method - it has to be called on an existing object, which means that's the value you should be formatting. So you'd call new Time(5, 10).ToString() for example - and that should format 5 hours and 10 minutes. — Jon Skeet
– Jon Skeet, Commented Jul 18, 2022 at 6:39

Enigmativity · Accepted Answer · 2022-07-18 07:06:31Z

3

You just need this implementation of your struct:

public readonly struct Time
{
    private readonly int _minutes;

    public Time(int minutes) : this(0, minutes) { }

    public Time(int hours, int minutes)
    {
        _minutes = (hours * 60 + minutes) % (24 * 60);
    }

    public int Hours => _minutes / 60;
    public int Minutes => _minutes % 60;
    public override string ToString() => $"{this.Hours:00}:{this.Minutes:00}";
}

When I run this code:

Console.WriteLine(new Time(8, 45).ToString());
Console.WriteLine(new Time(25, 160).ToString());

I get the following output:

08:45
03:40

answered Jul 18, 2022 at 7:06

Enigmativity

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9 Comments

Akzhol Over a year ago

This implementation looks so much better, but I am still unsure on how to inject values from a new object into a string format. Is that even possible? Something like return $"Object value1: {newobj.value1} Object value2: {newobj.value2}" No matter how much I search I can't find examples of code that does something similar to that or any explanations regarding it.

Akzhol Over a year ago

Another thing, how did you use/call the constructor without creating a new object? Was the constructor called automatically when the struct was created?

Enigmativity Over a year ago

@Akzhol You seem to have the idea: $"Text: {obj.Value}" is the way to go.

Enigmativity Over a year ago

@Akzhol - I don't know what you mean by "call the constructor without creating a new object". I did create a new object.

Akzhol Over a year ago

I thought objects need to be created with new or base, so where or how did you create it there? Sorry if I am annoying.

|

Hans Keﬆing · Accepted Answer · 2022-07-18 06:58:32Z

1

You can implement the standard ToString method like this:

public override string ToString()
{
   return $"{this.Hours:00}:{this.Minutes:00}";
}

or equivalent:

public override string ToString()
{
   return String.Format("{0:00}:{1:00}", this.Hours, this.Minutes);
}

The override keyword is required because you override the default ToString method
It doesn't need parameters, because it reads the local properties (this.Minutes and this.Hours - you can omit the "this."). Plus the standard ToString doesn't take parameters
The first one uses an interpolated string, the second example uses String.Format
In both cases the :00 means "format as two digits, adding leading 0's as needed" (docs)
Bonus: the debugger will use this method to display the value of this type

edited Jul 18, 2022 at 6:58

answered Jul 18, 2022 at 6:41

Hans Keﬆing

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Comments

Marcin Szubert · Accepted Answer · 2022-07-17 15:28:45Z

0

You can use built-in DateTime.ToString() with custom format. In your case it would look like:

int hour = 2;
int minute = 1;

DateTime time = new DateTime(2000, 1, 1, hour, minute, 0);

Console.WriteLine(time.ToString("HH:mm")); // 02:01

answered Jul 17, 2022 at 15:28

Marcin Szubert

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3 Comments

Akzhol Over a year ago

I assume this would make returning the string easier, but I am not sure how to implement this in my method. I think I still need to make use of the constructor to change fields by making a new object of Time class, and then I would need to pass hour and minute values from that object when creating DateTime? So would it look something like DateTime time = new DateTime(2000, 1, 1, stringtimeobj.hour, stringtimeobj.minute, 0); return time.ToString("HH:mm") Would that work? Sorry if it doesn't make sense, I am still figuring it out

Enigmativity Over a year ago

This is a dangerous approach as it does not allow for your input of 25 hours and 160 minutes.

Marcin Szubert Over a year ago

@Enigmativity This is just a method to convert already calculated hour and minute to required string.

vaibhavit80 · Accepted Answer · 2022-07-18 10:12:44Z

0

Yep , you can use it like this way below

DateTime time = new DateTime(2000, 1, 1, stringtimeobj.Hours,stringtimeobj.Minutes, 0);  
return time.ToString("HH:mm");

answered Jul 18, 2022 at 10:12

vaibhavit80

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Comments

Enigmativity · Accepted Answer · 2022-07-18 07:09:14Z

-2

We need to do some checking. If "stringtimeobj.hours" is greater than 9, which is 10 to 24, then "{stringtimeobj.hours}" can be used.

Also, if "stringTimeobj.minutes" is greater than 9, that is, 10 to 60, then "{stringtimeobj.minutes}" can be used.

Something like that.

edited Jul 18, 2022 at 7:09

Enigmativity

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answered Jul 17, 2022 at 15:04

HazeFog

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