How to display float values in c#?

Question

I'm working with structs in c#, and when I want to display average grade of a student like "4.53", it prints "453". Here's the code:

using System;
using System.Buffers;

namespace Struct
{
    struct student
    {
        public string name, surname;
        public float average;
    }

    class Program
    {
        static void Main(string[] args)
        {
            student[] arr = new student[3];
            for (int i = 0; i < 2; i++)
            {
                Console.Write("name {0}. - ", i + 1);
                arr[i].name = Console.ReadLine();
                Console.Write("surname {0}. - ", i + 1);
                arr[i].surname = Console.ReadLine();
                Console.Write("average {0}. - ", i + 1);
                arr[i].average = float.Parse(Console.ReadLine());
            }

            for (int i = 0; i < 2; i++)
            {
                Console.WriteLine("{0} {1} - {2}", arr[i].name, arr[i].surname, arr[i].average);
            }
        }
    }
}

I also tried this:

Console.WriteLine(string.Format("{0} {1} - {2:.0#}", arr[i].name, arr[i].surname, arr[i].average));

but it's not working.

Most likely your input gets interpreted that way. Use the debugger to check! Also : Tell us about the region you're in.. For many non-us places input should be `4,53` — TaW, Nov 03 '20 at 16:42

score 0 · Accepted Answer · answered Nov 03 '20 at 16:49

arr[i].average = float.Parse(Console.ReadLine());

Those warnings you see aren't just for show, they're trying to explain to you why the code you wrote is objectively bad.

Specifically, you're reading a floating point value written by a human who doesn't write numbers correctly according to the country he lives in.

Since you don't provide this information, let's say you wrote 2.15 on the prompt where your country expects floating point numbers to be written as 2,15, and where the . character is the decimal separator instead. In this case, that average field would get the value 215, which is correct according to your localization rules.

The warning you ignored hints at one possible solution: specifying a culture information type yourself, in case when it doesn't match the system culture information, and one possible culture that's always a decent default is CultureInfo.InvariantCulture, which uses . for the decimal point and , for the decimal separator.

It does, my point was that the code wasn't correct because you didn't know you had to write it in that specific format. If you were to deploy it to users all over the world, everyone would have to know the specific format to write numbers in, so you either need to make it clear (regex masks, validation, etc), or you need to provide a standard format. — Blindy, Nov 03 '20 at 17:00

How to display float values in c#?

1 Answers1