CODEWITHSUNDEEP
c#
Kai
Kai

Reputation: 41

Argument is not used in format string

Hey guys I'm sure if this had been asked already, but I could not find it. If it's redundant I'm sorry. Please link me to it. My question is:

What does error "Argument is not used in format string" mean? I am using C#

using System;

class PrintNum
{


    static void Main()
    {

        short s = 10;
        int i = 1000;
        long l = 1000000;
        float f = 230.47f;
        double d = 30949.374;


        //This is where I'm getting the error. 
        Console.Write("s: %d\n", s); //<<< if you hover over the variable s on the outside.
        Console.Write("i: %d\n", i);
        Console.Write("l: %ld\n", l);
        Console.Write("f: %.3f\n", f);
        Console.Write("d: %.3f\n", d);

    }
}

Upvotes: 1

Views: 3669

Answers (3)

Ben Richards
Ben Richards

Reputation: 3575

Like the other answers says, your Console.Write needs to include "{0}" as that is the placeholder for the variable your are writing. It's important to note that {0}, {1}, etc, are positional parameters and that order must be followed inside your string. It's also important to know that Console.Write uses String.Format underneath so you can use use all the format strings described at Standard Numeric Format Strings (https://msdn.microsoft.com/en-us/library/dwhawy9k(v=vs.110).aspx.) That being said, I think this is what you are looking for:

sing System;

public class Test
{
    public static void Main()
    {
        short s = 10;
        int i = 1000;
        long l = 1000000;
        float f = 230.47f;
        double d = 30949.374;

        Console.WriteLine("s: {0:D}", s);
        Console.WriteLine("i: {0:D}", i);
        Console.WriteLine("l: {0:D}", l);
        Console.WriteLine("f: {0:F}", f);
        Console.WriteLine("d: {0:F}", d);
    }
}

Output:

s: 10
i: 1000
l: 1000000
f: 230.47
d: 30949.37

Upvotes: 0

Jonesopolis
Jonesopolis

Reputation: 25370

use {0} to plug your argument into the string, 0 being the argument number:

Console.Write("s: {0}\n", s);

Check the documentation if you want to further format your number.

Also, there is a Console.WriteLine method that will save you from adding line breaks at the end of your string.

Upvotes: 0

Andrey Korneyev
Andrey Korneyev

Reputation: 26846

Your format string is incorrect. It should be something like

Console.Write("s: {0}\n", s);

where {0} in format string stands for "first parameter passed after format string", {1} is for second parameter (if any) and so on.

Unlike in C, %d and similar formatting parameters are not used in C# format strings and this formatting are handled with ToString method override of types you're using.

Upvotes: 3

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