How to calculate in c# the possibility of this game
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Right now im at this:
private int CalculateProbabilityOfDrawNumbersFromAllNumbers(int drawNumbers, int allNumbers) { return ((Factorial(allNumbers) \* Factorial(80 - allNumbers)) / (((Factorial(80) \* ((Factorial(drawNumbers) \* Factorial(allNumbers - drawNumbers)) \* (Factorial(20 - drawNumbers) \* Factorial(((80 - allNumbers) - (20 - drawNumbers)))))) / (Factorial(20) \* Factorial(80 - 20))))); } private static int Factorial(int x) { int f = 1; while (x > 1) { f \*= x--; } return f; }which gives division by zero and i try to understand if something have gone wrong with all those parenthesis
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Small hint: 80! is a number of about 120 decimal digits. An int can hold numbers up to roughly 9 digits.
that wasnt a hint!!! it appears to be the solution cause now this works
using System.IO;
using System;class Program
{
static void Main()
{
Console.WriteLine(CalculateProbabilityOfDrawNumbersFromAllNumbers(1,1));
}
private static double CalculateProbabilityOfDrawNumbersFromAllNumbers(double drawNumbers, double allNumbers)
{
return Factorial(allNumbers) / (Factorial(drawNumbers) * Factorial(allNumbers - drawNumbers)) * (Factorial(80 - allNumbers) / (Factorial(20 - drawNumbers) * Factorial(80 - allNumbers - (20 - drawNumbers)))) / (Factorial(80) / (Factorial(20) * Factorial(80 - 20)));
}private static double Factorial(double x) { double f = 1; while (x > 1) { f \*= x--; } return f; }}
im not sure why i was getting division by zero error. the int has surpass its largest number and return 0? i will use this crazy code to display it as a percentage without any unnecessary zeros in the end
Console.WriteLine((CalculateProbabilityOfDrawNumbersFromAllNumbers(12,12) \* 100).ToString("F7").TrimEnd(new Char\[\] { '0' } ).TrimEnd(new Char\[\] { '.' } )+"%"); -
that wasnt a hint!!! it appears to be the solution cause now this works
using System.IO;
using System;class Program
{
static void Main()
{
Console.WriteLine(CalculateProbabilityOfDrawNumbersFromAllNumbers(1,1));
}
private static double CalculateProbabilityOfDrawNumbersFromAllNumbers(double drawNumbers, double allNumbers)
{
return Factorial(allNumbers) / (Factorial(drawNumbers) * Factorial(allNumbers - drawNumbers)) * (Factorial(80 - allNumbers) / (Factorial(20 - drawNumbers) * Factorial(80 - allNumbers - (20 - drawNumbers)))) / (Factorial(80) / (Factorial(20) * Factorial(80 - 20)));
}private static double Factorial(double x) { double f = 1; while (x > 1) { f \*= x--; } return f; }}
im not sure why i was getting division by zero error. the int has surpass its largest number and return 0? i will use this crazy code to display it as a percentage without any unnecessary zeros in the end
Console.WriteLine((CalculateProbabilityOfDrawNumbersFromAllNumbers(12,12) \* 100).ToString("F7").TrimEnd(new Char\[\] { '0' } ).TrimEnd(new Char\[\] { '.' } )+"%");Quote:
im not sure why i was getting division by zero error. the int has surpass its largest number and return 0?
Don't just let that go, think, think until you figured it out!
Luc Pattyn [My Articles] If you can't find it on YouTube try TikTok...
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So what's the problem? that link leads you through the process of getting a probability from the inputs, so what have you tried to implement it? Where are you stuck? What help do you need? (Other than "somebody else to do all the work for me" which isn't the idea of this site at all.)
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt AntiTwitter: @DalekDave is now a follower!
can you say it 10 more times :P i think it will help
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that wasnt a hint!!! it appears to be the solution cause now this works
using System.IO;
using System;class Program
{
static void Main()
{
Console.WriteLine(CalculateProbabilityOfDrawNumbersFromAllNumbers(1,1));
}
private static double CalculateProbabilityOfDrawNumbersFromAllNumbers(double drawNumbers, double allNumbers)
{
return Factorial(allNumbers) / (Factorial(drawNumbers) * Factorial(allNumbers - drawNumbers)) * (Factorial(80 - allNumbers) / (Factorial(20 - drawNumbers) * Factorial(80 - allNumbers - (20 - drawNumbers)))) / (Factorial(80) / (Factorial(20) * Factorial(80 - 20)));
}private static double Factorial(double x) { double f = 1; while (x > 1) { f \*= x--; } return f; }}
im not sure why i was getting division by zero error. the int has surpass its largest number and return 0? i will use this crazy code to display it as a percentage without any unnecessary zeros in the end
Console.WriteLine((CalculateProbabilityOfDrawNumbersFromAllNumbers(12,12) \* 100).ToString("F7").TrimEnd(new Char\[\] { '0' } ).TrimEnd(new Char\[\] { '.' } )+"%");im 99,99 percent sure that on overflow int will return 0 or -1 :P so this should be the issue
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im 99,99 percent sure that on overflow int will return 0 or -1 :P so this should be the issue
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It depends what it overflows from. For example if you add 1 to 2147483647 you will get -2147483648.
Wow it really works as the counters we have in cars that counts kilometers? They start all over again from the beginning, only for integers we also have negative ones
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im 99,99 percent sure that on overflow int will return 0 or -1 :P so this should be the issue
That is absolutely false. Your 99.99 percent isn't worth much, you haven't understood how integers typically work. Think again, and if necessary: experiment, observe, but stop guessing and "being sure". Here are three questions for you, first think about them; the answer is simple when you reason correctly. If you can't solve it, then try it, and search the explanation: 1. we all expect n! to be larger than (n-1)! and yet, with your original implementation this is not true for n=14, the value isn't larger, it is about 33% less!!! 2. multiplying positive numbers cannot ever yield a negative, and yet your code will claim 19! to be negative (no, not -1). 3. And finally, why is 34! the first one that returns zero... :)
Luc Pattyn [My Articles] If you can't find it on YouTube try TikTok...
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Wow it really works as the counters we have in cars that counts kilometers? They start all over again from the beginning, only for integers we also have negative ones
Exoskeletor wrote:
Wow it really works as the counters we have in cars that counts kilometers?
Ehr.. no. Just look up how a PC stores numbers in binary, and the limitations of each number-"type".
Bastard Programmer from Hell :suss: "If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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Exoskeletor wrote:
Wow it really works as the counters we have in cars that counts kilometers?
Ehr.. no. Just look up how a PC stores numbers in binary, and the limitations of each number-"type".
Bastard Programmer from Hell :suss: "If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
There was a time i new all those things in university but years have passed since, ok i have look them up
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That is absolutely false. Your 99.99 percent isn't worth much, you haven't understood how integers typically work. Think again, and if necessary: experiment, observe, but stop guessing and "being sure". Here are three questions for you, first think about them; the answer is simple when you reason correctly. If you can't solve it, then try it, and search the explanation: 1. we all expect n! to be larger than (n-1)! and yet, with your original implementation this is not true for n=14, the value isn't larger, it is about 33% less!!! 2. multiplying positive numbers cannot ever yield a negative, and yet your code will claim 19! to be negative (no, not -1). 3. And finally, why is 34! the first one that returns zero... :)
Luc Pattyn [My Articles] If you can't find it on YouTube try TikTok...
Overflow could cause positive + positive to be negative and the other way around from what i have read.
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Overflow could cause positive + positive to be negative and the other way around from what i have read.
Certainly - and you would have an overflow exception as well. Unless you deliberately overlook it. If you don't specify any handling, but some default handler is called, it depends on this handler where execution continues. Maybe the storing of the (overflowed) result is skipped. If the sum variable was initially zero it may still be zero, if nothing is stored. Then: A factorial is never negative. So is it appropriate handle it as signed value at all? (You may still have an overflow, but if you ignore it, you have a true wraparound effect, like your car odometer)
