C#•2y ago

✅ runtime error

using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Collections;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization;
using System.Text.RegularExpressions;
using System.Text;
using System;

class Result
{

    /*
     * Complete the 'plusMinus' function below.
     *
     * The function accepts INTEGER_ARRAY arr as parameter.
     */

    public static void plusMinus(List<int> arr)
    {
        int positive = 0;
        int negative = 0;
        int zero = 0;

        for (int i = 0; i > arr.Count; i++)
        {
            if (arr[i] < 0)
            {
                negative++;
            }
            else if (arr[i] > 0)
            {
                positive++;
            }
            else if (arr[i] == 0)
            {
                zero++;
            }

        }
        Console.WriteLine(string.Format("{0.0.000000}\n", (positive / arr.Count)) + string.Format("{0.0.000000}\n", (negative / arr.Count)) + string.Format("{0.0.000000}",zero/arr.Count));
    }

}

class Solution
{
    public static void Main(string[] args)
    {
        int n = Convert.ToInt32(Console.ReadLine().Trim());

        List<int> arr = Console.ReadLine().TrimEnd().Split(' ').ToList().Select(arrTemp => Convert.ToInt32(arrTemp)).ToList();

        Result.plusMinus(arr);
    }
}

using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Collections;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization;
using System.Text.RegularExpressions;
using System.Text;
using System;

class Result
{

    /*
     * Complete the 'plusMinus' function below.
     *
     * The function accepts INTEGER_ARRAY arr as parameter.
     */

    public static void plusMinus(List<int> arr)
    {
        int positive = 0;
        int negative = 0;
        int zero = 0;

        for (int i = 0; i > arr.Count; i++)
        {
            if (arr[i] < 0)
            {
                negative++;
            }
            else if (arr[i] > 0)
            {
                positive++;
            }
            else if (arr[i] == 0)
            {
                zero++;
            }

        }
        Console.WriteLine(string.Format("{0.0.000000}\n", (positive / arr.Count)) + string.Format("{0.0.000000}\n", (negative / arr.Count)) + string.Format("{0.0.000000}",zero/arr.Count));
    }

}

class Solution
{
    public static void Main(string[] args)
    {
        int n = Convert.ToInt32(Console.ReadLine().Trim());

        List<int> arr = Console.ReadLine().TrimEnd().Split(' ').ToList().Select(arrTemp => Convert.ToInt32(arrTemp)).ToList();

        Result.plusMinus(arr);
    }
}

I made this algorithm that is supposed to receive an input and gather all the negative numbers into one variable and positive variables into another. in then divided it by the number of items in the given list.

73 Replies

shawski.•2y ago

This error was thrown however

Unhandled exception. System.FormatException: Input string was not in a correct format.
   at System.Text.ValueStringBuilder.ThrowFormatError()
   at System.Text.ValueStringBuilder.AppendFormatHelper(IFormatProvider provider, String format, ParamsArray args)
   at System.String.FormatHelper(IFormatProvider provider, String format, ParamsArray args)
   at System.String.Format(String format, Object arg0)
   at Result.plusMinus(List`1 arr) in /tmp/submission/20221204/23/03/hackerrank-12ebdeb1541a3d3b298eaa5a029f1ef7/code/Solution.cs:line 46
   at Solution.Main(String[] args) in /tmp/submission/20221204/23/03/hackerrank-12ebdeb1541a3d3b298eaa5a029f1ef7/code/Solution.cs:line 59
Aborted (core dumped)

Unhandled exception. System.FormatException: Input string was not in a correct format.
   at System.Text.ValueStringBuilder.ThrowFormatError()
   at System.Text.ValueStringBuilder.AppendFormatHelper(IFormatProvider provider, String format, ParamsArray args)
   at System.String.FormatHelper(IFormatProvider provider, String format, ParamsArray args)
   at System.String.Format(String format, Object arg0)
   at Result.plusMinus(List`1 arr) in /tmp/submission/20221204/23/03/hackerrank-12ebdeb1541a3d3b298eaa5a029f1ef7/code/Solution.cs:line 46
   at Solution.Main(String[] args) in /tmp/submission/20221204/23/03/hackerrank-12ebdeb1541a3d3b298eaa5a029f1ef7/code/Solution.cs:line 59
Aborted (core dumped)

for example

6
-4 3 -9 0 4 1

6
-4 3 -9 0 4 1

if given an input like this

0.500000
0.333333
0.166667

0.500000
0.333333
0.166667

It should print this

Angius•2y ago

Use $tryparse

MODiX•2y ago

The TryParse pattern is considered best practice of parsing data from a string: - a TryParse method returns true or false to inform you if it succeeded or not, so you can use it directly in a condition, - since C# 7 you can declare a variable that will be used as an out argument inline in an argument list, - it forces you to check if the out argument contains valid data afterwards, Avoid: Convert.ToInt32 — it's a bad choice for parsing an int. It exists only for backwards compatibility reasons and should be considered last resort.

return Convert.ToInt32(null); //returns 0. null should not be considered as 0 ever
return Convert.ToInt32("asdf"); //throws FormatException

return Convert.ToInt32(null); //returns 0. null should not be considered as 0 ever
return Convert.ToInt32("asdf"); //throws FormatException

(Note: Convert does contain useful conversion methods: To/FromBase64String, To/FromHexString, ToString(X value, int toBase), ToX(string? value, int fromBase)) Avoid: int.Parse — you have to use a try/catch statement to handle invalid input, which is a less clean solution.

var number = int.Parse("abc"); //throws FormatException
var number = int.Parse(""); //throws FormatException

var number = int.Parse("abc"); //throws FormatException
var number = int.Parse(""); //throws FormatException

Use int.TryParse https://docs.microsoft.com/en-us/dotnet/api/system.int32.tryparse?view=net-5.0#System_Int32_TryParse_System_String_System_Int32__

if (int.TryParse(someInput, out var result))
{
  Console.WriteLine($"Thanks for giving me the following number: {result}!");
}
else
{
  Console.WriteLine("You didn't give me a valid number :c");
}

if (int.TryParse(someInput, out var result))
{
  Console.WriteLine($"Thanks for giving me the following number: {result}!");
}
else
{
  Console.WriteLine("You didn't give me a valid number :c");
}

Int32.TryParse Method (System)

Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the operation succeeded.

Angius•2y ago

Convert.ToWhatever() throws whatever.TryParse() doesn't, just returns false Also, run the debugger to see what exactly causes this error

shawski.•2y ago

alright

Angius•2y ago

Some of the things you're trying to parse to an integer, isn't a valid integer

shawski.•2y ago

theres a couple things i should say so the main method wasnt written by me i am solving a problem and that's just how it was im only editing the plusMinus method

Angius•2y ago

Cool cool The answer remains

shawski.•2y ago

wait then wdym dont use Int.Parse or Convert.ToInt32?

Angius•2y ago

Line 46 That's where the issue is

shawski.•2y ago

Console.WriteLine(string.Format("{0.0.000000}\n", (positive / arr.Count)) + string.Format("{0.0.000000}\n", (negative / arr.Count)) + string.Format("{0.0.000000}", zero / arr.Count)));

Console.WriteLine(string.Format("{0.0.000000}\n", (positive / arr.Count)) + string.Format("{0.0.000000}\n", (negative / arr.Count)) + string.Format("{0.0.000000}", zero / arr.Count)));

thats line 46

Angius•2y ago

int.Parse(
    string.Format("{0.0.000000}\n", (positive / arr.Count)) +     string.Format("{0.0.000000}\n", (negative / arr.Count)) +     string.Format("{0.0.000000}", zero / arr.Count)
)

int.Parse(
    string.Format("{0.0.000000}\n", (positive / arr.Count)) +     string.Format("{0.0.000000}\n", (negative / arr.Count)) +     string.Format("{0.0.000000}", zero / arr.Count)
)

Yeah Well The result of appending those three formatted strings will never in a million years be a valid integer It has dots, it has new lines, it has all sorts of things What looks like

8.93712
9.12342
0.11982

8.93712
9.12342
0.11982

is as far removed from being an integer as something vaguely numeric can possibly be

shawski.•2y ago

yes

Angius•2y ago

Why do you even want to parse it to an integer? It doesn't seem necessary

shawski.•2y ago

i wasnt trying to. i sent u the code where i had that there

Angius•2y ago

shawski.•2y ago

refer to the code i sent in the description of this post as the most up to date one

Angius•2y ago

So... why did you say line 46 has the int.Parse() in it..? If the most recent code doesn't..?

shawski.•2y ago

im not sure. i put it by accident i think

Angius•2y ago

So line 46, even without int.Parse(), still throws the format error?

shawski.•2y ago

Unhandled exception. System.FormatException: Input string was not in a correct format.
   at System.Text.ValueStringBuilder.ThrowFormatError()
   at System.Text.ValueStringBuilder.AppendFormatHelper(IFormatProvider provider, String format, ParamsArray args)
   at System.String.FormatHelper(IFormatProvider provider, String format, ParamsArray args)
   at System.String.Format(String format, Object arg0)
   at Result.plusMinus(List`1 arr) in /tmp/submission/20221204/23/30/hackerrank-a170d9b68469cb16ffbb9fd7bfb6de66/code/Solution.cs:line 46
   at Solution.Main(String[] args) in /tmp/submission/20221204/23/30/hackerrank-a170d9b68469cb16ffbb9fd7bfb6de66/code/Solution.cs:line 59
Aborted (core dumped)

Unhandled exception. System.FormatException: Input string was not in a correct format.
   at System.Text.ValueStringBuilder.ThrowFormatError()
   at System.Text.ValueStringBuilder.AppendFormatHelper(IFormatProvider provider, String format, ParamsArray args)
   at System.String.FormatHelper(IFormatProvider provider, String format, ParamsArray args)
   at System.String.Format(String format, Object arg0)
   at Result.plusMinus(List`1 arr) in /tmp/submission/20221204/23/30/hackerrank-a170d9b68469cb16ffbb9fd7bfb6de66/code/Solution.cs:line 46
   at Solution.Main(String[] args) in /tmp/submission/20221204/23/30/hackerrank-a170d9b68469cb16ffbb9fd7bfb6de66/code/Solution.cs:line 59
Aborted (core dumped)

error with int.Parse removed

Angius•2y ago

Ah, I see what the issue is I didn't see it initially because I never use string.Format() since string interpolation exists "{0.0.000000}\n" should be "{0:0.000000}\n"

shawski.•2y ago

do you suggest i use string interpolation instead?

Angius•2y ago

Yes

shawski.•2y ago

im not sure how to do it with that oh thats what i messed up on. ty i kind of was doing that from mostly memory

MODiX•2y ago

Angius#1586

REPL Result: Success

var num = 8.824;
Console.WriteLine(string.Format("Number {0:0.00000}", num));
Console.WriteLine($"Number {num:0.00000}");

var num = 8.824;
Console.WriteLine(string.Format("Number {0:0.00000}", num));
Console.WriteLine($"Number {num:0.00000}");

Console Output

Number 8.82400
Number 8.82400

Number 8.82400
Number 8.82400

Compile: 590.156ms | Execution: 74.727ms | React with ❌ to remove this embed.

Angius•2y ago

Here's how to achieve the same with string interpolation

shawski.•2y ago

holy that is soo much more clean

shawski.•2y ago

why did it return all 0s?

shawski.•2y ago

int positive = 0;
        int negative = 0;
        int zero = 0;

        for (int i = 0; i > arr.Count; i++)
        {
            if (arr[i] < 0)
            {
                negative++;
            }
            else if (arr[i] > 0)
            {
                positive++;
            }
            else if (arr[i] == 0)
            {
                zero++;
            }
        }

int positive = 0;
        int negative = 0;
        int zero = 0;

        for (int i = 0; i > arr.Count; i++)
        {
            if (arr[i] < 0)
            {
                negative++;
            }
            else if (arr[i] > 0)
            {
                positive++;
            }
            else if (arr[i] == 0)
            {
                zero++;
            }
        }

i loop over all the elements to get how many positives, negatives, and 0s there are

Angius•2y ago

What's your string? Seems something wrong with the output string, not with the values Although you can, of course, make sure by using the debugger

shawski.•2y ago

Console.WriteLine(string.Format("{0:0.000000}\n", (positive / arr.Count))

Console.WriteLine(string.Format("{0:0.000000}\n", (positive / arr.Count))

this is how i calculate the output for positive numbres

Angius•2y ago

Ah, so you didn't use string interpolation

shawski.•2y ago

not yet

Angius•2y ago

I thought that might've been the issue

shawski.•2y ago

ill change it to that rn

Angius•2y ago

Ah, I know why Integer division Cast one of the operands to a double (double)positive / arr.Count for example

shawski.•2y ago

alright

Console.WriteLine($"{(double)positive / arr.Count:0.000000}"

Console.WriteLine($"{(double)positive / arr.Count:0.000000}"

it prints "0.000000"

Angius•2y ago

Try

Console.WriteLine($"{((double)positive / arr.Count):0.000000}"

Console.WriteLine($"{((double)positive / arr.Count):0.000000}"

Console.WriteLine($"{((double)positive) / arr.Count:0.000000}"

Console.WriteLine($"{((double)positive) / arr.Count:0.000000}"

Console.WriteLine($"{(double)positive / (double)arr.Count:0.000000}"

Console.WriteLine($"{(double)positive / (double)arr.Count:0.000000}"

Console.WriteLine($"{((double)positive / (double)arr.Count):0.000000}"

Console.WriteLine($"{((double)positive / (double)arr.Count):0.000000}"

Some parentheses here and there might help

shawski.•2y ago

tried those all same result

Angius•2y ago

Huh

MODiX•2y ago

Angius#1586

REPL Result: Success

int a = 1;
int b = 9;
($"{(double)a / b:0.000000}", $"{a / (double)b:0.000000}")

int a = 1;
int b = 9;
($"{(double)a / b:0.000000}", $"{a / (double)b:0.000000}")

Result: ValueTuple<string, string>

{
  "item1": "0.111111",
  "item2": "0.111111"
}

{
  "item1": "0.111111",
  "item2": "0.111111"
}

Compile: 523.124ms | Execution: 48.761ms | React with ❌ to remove this embed.

Angius•2y ago

It should work just fine

shawski.•2y ago

yeah i would think so. im not sure where i messed up.

Angius•2y ago

I guess you could try pulling that (double)positive / arr.Count to a variable and using the debugger to check what the value is

shawski.•2y ago

alr

Angius•2y ago

Maybe it's so small that 6 decimal places is not enough to show anything

shawski.•2y ago

i might need a little break. been going at this for a while. my brain is tired.

Angius•2y ago

Yeah, get a break, drink some water, come back to it when you feel like it

shawski.•2y ago

alright thank you for helping me

shawski.•2y ago

shawski.•2y ago

i did some debugging i just made a list to test this code there are 2 positive numbers and 1 zero i made a break point when it reaches line 41, positive = 0 how does that make sense positive should be 2 in this case @Angius i think thats been my problem this whole time although i cant see a reason why it would be 0

Angius•2y ago

That does seem super weird indeed I'd probably start by turning that for loop into a foreach, just to make sure it's not an issue Doesn't seem to be and probably isn't But it's best to get rid of as many moving parts as possible

shawski.•2y ago

alright i dont think ive ever used a foreach let me figure it out gimme a sec

Angius•2y ago

Let's you avoid the issue that @Box⸬læk⸬<'static>(Box⸬new(Aaron⸩ pointed out, with

shawski.•2y ago

turning that into a less than seemed to fix it i thought it was a greater than tho i guess i just forgot the syntax a little..

Angius•2y ago

Loop runs as long as that condition is true It's a run condition, not a stop condition Also, foreach just does that all for you lol

shawski.•2y ago

should i use foreach rather than a for loop when i can? im more familiar with for loops

Angius•2y ago

Foreach is much easier to use Use whatever suits you, through, and learn as you go

shawski.•2y ago

all my tests pass after changing the greater than symbol to less than in the for loop :/ such a little thing i missed that took me this long.. im gonna try to replicate this with a foreach and see which one i like more

Angius•2y ago

It's always the little things lol

shawski.•2y ago

shawski.•2y ago

i figured foreach out pretty quick that seems much easier are there cases where one is objectively better than the other?

Angius•2y ago

Pretty much always foreach Unless you need the index, then for

shawski.•2y ago

the index? yeah the tests all passed with the foreach. wow that was a lot cleaner

Angius•2y ago

The number of the element in the collection

shawski.•2y ago

oh yeah is there an alternative to all those if statements?

Angius•2y ago

I'd probably use a switch expression That said, I'm on mobile now, so it'd be hard to write it out lol I'll let you do some googling, and if nothing comes up, I'll write the code up when I'm at my PC again

shawski.•2y ago

alright

Angius•2y ago

Ah, no, wait, a switch expression probably won't work here... unless we get fancy with tuple deconstruction Those ifs are prolly your best bet Easiest to understand and work just fine I'd maybe turn the last else if into just an else

shawski.•2y ago

yeah i was about to say i have no idea how im gonna use a switch here lol good point. not sure why i had it typed like that. @Angius is there a method that i can utilize to round to the nearest 5? here actually imma close this. im done with that problem. ill open a new one if i need help with something else

Accord•2y ago

Closed!

Gaming

Programming

✅ runtime error