We Keep Coding

Maximum product of 13 adjacent numbers

List<int> arr = new List<int>();
long max = 0;
long mul = 1;
string abc = #"73167176531330624919225119674426574742355349194934
85861560789112949495459501737958331952853208805511
96983520312774506326239578318016984801869478851843
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450";
foreach (char a in abc)
{
if(arr.Count == 13)
{
arr.RemoveAt(0);
}
int value = (int)Char.GetNumericValue(a);
arr.Add(value);
if(arr.Count == 13)
{
foreach(int b in arr)
{
mul = mul * b;
if (mul > max)
{
max = mul;
}
}
mul = 1;
}
}
Console.WriteLine(max);
I am getting 5377010688 which is a wrong answer and when I am trying same logic with given example in project Euler it is working fine, please help me.
Don't say the answer just correct me where I am doing wrong or where the code is not running as it should.

The string constant, as it is written down like above, contains blanks and \r\n's, e.g. between the last '4' of the first line and the first '8' on the second line. Char.GetNumericValue() returns -1 for a blank.
Propably the character sequence with the highest product spans across adjacent lines in your string, therefore there are blanks in between, which count as -1, which disables your code in finding them.
Write your constant like this:
string abc = #"73167176531330624919225119674426574742355349194934" +
"85861560789112949495459501737958331952853208805511" +
"96983520312774506326239578318016984801869478851843" + etc.
The result is then 23514624000, I hope that's correct.

Don't say the answer just correct me where I am doing wrong or where
the code is not running as it should
You have included all characters into calculation but you should not do that. The input string also contains for example carriage return '\n' at the end of each line.
Your actual string look like this:
string abc = #"73167176531330624919225119674426574742355349194934\r\n
85861560789112949495459501737958331952853208805511\r\n
...
How to solve this? You should ignore these characters, one possible solution is to check each char if it is a digit:
if(!char.IsDigit(a))
{
continue;
}

How to format numbers in scientific notation with powers in superscript

I need to write values like:
9.6 x 10²
9.6 x 10¹²
I need to know if there is a way to format numbers as above in a string.

You have to find the appropriate character from the code page you are using, for example UTF-8:
string superScript2 = "²";
There is no such thing as formatting in a string, it is just all data.

Try this:
public static string Eng(this double x, string format="g")
{
const string sup_signs = "⁺⁻⁼⁽⁾ⁿ";
const string sup_digits = "⁰¹²³⁴⁵⁶⁷⁸⁹";
if(double.IsNaN(x) || double.IsInfinity(x))
{
return x.ToString();
}
int num_sign = Math.Sign(x);
x = Math.Abs(x);
// group exponents in multiples of 3 (thousands)
int exp = (int)Math.Floor(Math.Log(x, 10)/3)*3;
// otherwise use:
// int exp = (int)Math.Floor(Math.Log(x, 10));
// and handle the exp==1 case separetly to avoid 10¹
x*= Math.Pow(10, -exp);
int exp_sign = Math.Sign(exp);
exp = Math.Abs(exp);
// Build the exponent string 'dig' from right to left
string dig = string.Empty;
while(exp>0)
{
int n = exp%10;
dig = sup_digits[n] + dig;
exp = exp/10;
}
// if has exponent and its negative prepend the superscript minus sign
if(dig.Length>0 && exp_sign<0)
{
dig = sup_signs[1] + dig;
}
// prepend answer with minus if number is negative
string sig = num_sign<0 ? "-" : "";
if(dig.Length>0)
{
// has exponent
return $"{sig}{x.ToString(format)}×10{dig}";
}
else
{
// no exponent
return $"{sig}{x.ToString(format)}";
}
}
As a test case run
static void Main(string[] args)
{
// Type code here.
double x = Math.PI/50e5;
for(int i = 0; i < 20; i++)
{
// Format output to 12 wide column, right aligned
Debug.WriteLine($"{ Eng(x, "g4"),12}");
x*=50;
}
}
with the output:
628.3×10⁻⁹
31.42×10⁻⁶
1.571×10⁻³
78.54×10⁻³
3.927
196.3
9.817×10³
490.9×10³
24.54×10⁶
1.227×10⁹
61.36×10⁹
3.068×10¹²
153.4×10¹²
7.67×10¹⁵
383.5×10¹⁵
19.17×10¹⁸
958.7×10¹⁸
47.94×10²¹
2.397×10²⁴
119.8×10²⁴
By no means optimized, but it does the job. The exponents are in engineering form (multiples of 3 only, in order to avoid things like 10¹). As a bonus, the number can be formatted to a specific number of significant digits by supplying a format code like g4 or g5 for 4 or 5 digits respectively.
It can handle negative or positive numbers
It can handle negative or positive exponents of 10
In can format the mantissa
It can handle NAN or Inf.
It's in extension form for re-usability

As a follow up to my comment above - does something like this do what you require :
public String FormatAs10Power(decimal val)
{
string SuperscriptDigits = "\u2070\u00b9\u00b2\u00b3\u2074\u2075\u2076\u2077\u2078\u2079";
string expstr = String.Format("{0:0.#E0}", val);
var numparts = expstr.Split('E');
char[] powerchars = numparts[1].ToArray();
for (int i = 0; i < powerchars.Length; i++)
{
powerchars[i] = (powerchars[i] == '-') ? '\u207b' : SuperscriptDigits[powerchars[i] - '0'];
}
numparts[1] = new String(powerchars);
return String.Join(" x 10",numparts);
}
See : https://dotnetfiddle.net/dX7LAF
As per my comment above - the number is first converted to an exponential format string (https://learn.microsoft.com/en-us/dotnet/standard/base-types/standard-numeric-format-strings#EFormatString), that string is then split on the exponential separator 'E'. The first array is the numeric part, the second the power of 10 to which it is raised - this is converted to superscript characters using one of the techniques of the link I gave (Convert a string/integer to superscript in C#), converted back to a string & the two parts combined using "x 10" as the new separator.
I have assumed you want the value to single digit precision as per your example with no preceding + sign. If you need anything else you could pass the format as a parameter. The code for superscript + is '\u207A'. There is a link here (at the time of writing) giving the list of superscript codes : http://unicode.org/charts/PDF/U2070.pdf

Determine a numeric range that may contain alpha and numeric characters

I am not even sure how to phrase this question so I apologize in advance. I have a form used by our QA. it requires input of serial numbers - a lot of them (sometimes hundreds). I have two text boxes on the form for lower and upper numbers in the range (doesn't have to be this way but it is my best guess). I know how to to do this if it were just integers (see code below) but that is not the only format.Examples of the format could include a date code ("170508/1234") or could include alpha characters (ABC1234). there is a wide variety of formats but in every case, I want to find the range from the last set of numbers (typically last four digits - Like "170508/1234 170508/1235... and ABC1234 ABC1235 ... not to exclude 1234 1235 ....).
Thank you in advance
private void btnSN_Click(object sender, EventArgs e)
{
int from = Convert.ToInt32(txtSnStart.Text.Trim());
int to = Convert.ToInt32(txtSnEnd.Text.Trim());
for (int i = from; i <= to; i++)
{
txtSN.Text += i.ToString() +" ";
}

You can make use of RexEx for this, the RegEx expression below should match any number of digits at the end.:
(\d+)$
Here is the modified code:
// find the group of digits at end of entered text
var fromMatch = Regex.Match(txtSnStart.Text.Trim(), #"(\d+)$");
int from = Convert.ToInt32(fromMatch.Groups[1].Value);
// strip the matched digit group from entered text to get the prefix
string prefix = txtSnStart.Text.Trim().SubString(0, txtSnStart.Text.Trim().LastIndexOf(from.ToString()));
var toMatch = Regex.Match(txtSnEnd.Text.Trim(), #"(\d+)$");
int to = Convert.ToInt32(toMatch.Groups[1].Value);
for (int i = from; i <= to; i++)
{
// combine the prefix and range value
txtSN.Text += string.Format("{0}{1} ", prefix, i.ToString());
}

This problem becomes easier if you break it into smaller pieces.
This will become especially important once it becomes apparent that one small part of the problem might become more complex.
The inputs are a prefix, a number to begin the range, and a number to end the range. Given that, here's a class with a function to return those strings:
public class StringRangeCreator
{
public IEnumerable<string> CreateStringRange(
string prefix, int rangeStart, int rangeEnd)
{
if (rangeStart > rangeEnd) throw new ArgumentException(
$"{nameof(rangeStart)} cannot be greater than {nameof(rangeEnd)}");
return Enumerable.Range(rangeStart, (rangeEnd-rangeStart) + 1)
.Select(n => prefix + n);
}
}
Enumerable.Range creates a range of numbers. The Select takes that range and returns a set of strings consisting of the prefix concatenated with the number in the range.
And a unit test to make sure it works:
[TestClass]
public class DetermineRangeFromLastFourCharacters
{
[TestMethod]
public void ReturnsExpectedRangeOfStrings()
{
var result = new StringRangeCreator().CreateStringRange("abc", 1, 10).ToList();
Assert.AreEqual(10, result.Count);
Assert.AreEqual("abc1", result[0]);
Assert.AreEqual("abc10", result[9]);
}
}
But if these are serial numbers then you maybe you don't want ABC8, ABC9, ABC10. You might want ABC08, ABC09, ABC10. All the same length.
So here's the modified class. I'm guessing a little at what the expected behavior might be. It lets you specify an optional minimum number of digits so that you can pad accordingly:
public class StringRangeCreator
{
public IEnumerable<string> CreateStringRange(
string prefix, int rangeStart, int rangeEnd, int minimumDigits = 1)
{
if (rangeStart > rangeEnd) throw new ArgumentException(
$"{nameof(rangeStart)} cannot be greater than {nameof(rangeEnd)}");
return Enumerable.Range(rangeStart, (rangeEnd-rangeStart) + 1)
.Select(n => prefix + n.ToString("0").PadLeft(minimumDigits, '0'));
}
}
And another unit test:
[TestMethod]
public void PadsNumbersAccordingToParameter()
{
var result = new StringRangeCreator().CreateStringRange("abc", 999, 1001, 3).ToList();
Assert.AreEqual(3, result.Count);
Assert.AreEqual("abc999", result[0]);
Assert.AreEqual("abc1001", result[2]);
}
Some other scenarios you might want to account for are negative numbers or extremely large ranges.
Now that the problem of creating the result set is separated into a class with simple inputs and outputs that you can test, what remains is to take the input from the form and break it down into these inputs. That might include making sure that both strings have the same prefixes and making sure that the last parts of the strings are numbers.
But the whole thing will be a little simpler once it's not all in one big method. That also makes it easier to change when you realize something different about how you want it to work. Validating your input can be one step, and then getting the results can be another.
The unit tests help because you don't want to have to debug the whole thing to see if it works. Enumerable.Range didn't work the way I thought it did, so I had to fix a bug. It was easy to find and fix with the unit tests. It would have been harder if I had to run a whole app and then step through it in the debugger.

Create a numeric value from text

I have searched allot on google without any results I am looking for
I would like to get a numeric value from any string in C#
Ex.
var myString = "Oompa Loompa";
var numericoutput = convertStringToNumericValue(myString);
output/value of numericoutput is something like 612734818
so when I put in another string let say "C4rd1ff InTernaT!onal is # gr3at place#"
the int output will be something like 73572753.
The Values must stay constant, for example so if I enter the same text again of "Oompa Loompa" then I get 612734818 again.
I thought maybe in the way of using Font Family to get the char index of each character, but I don't know where to start with this.
The reason for this is so that I can use this number to generate an index out of a string with other data in it, and with the same input string, get that same index again to recall the final output string for validation.
Any help or point in the right direction would be greatly appreciated

Thanks to Tim I ended up doing the following:
var InputString = "My Test String ~!##$%^&*()_+{}:<>?|";
byte[] asciiBytes = Encoding.ASCII.GetBytes(InputString);
int Multiplier = 1;
int sum = 0;
foreach (byte b in asciiBytes)
{
sum += ((int)b) * Multiplier;
Multiplier++;
}
Obviously this will not work for 1000's of characters, but it is good enough for short words or sentences
int.MaxValue = 2 147 483 647

As an alternative to converting the string to it's bytes, and if a hash won't meet the requirements, here are a couple of shorter ways to accomplish getting a numeric value for a string:
string inputString = "My Test String ~!##$%^&*()_+{}:<>?|"
int multiplier = 0;
int sum = 0;
foreach (char c in inputString)
{
sum += ((int)c) * ++multiplier;
}
The above code outputs 46026, as expected. The only difference is it loops through the characters in the string and gets their ASCII value, and uses the prefix ++ operator (Note that multiplier is set to 0 in this case - which is also the default for int).
Taking a cue from Damith's comment above, you could do the same with LINQ. Simply replace the foreach above with:
sum = inputString.Sum(c => c * ++multiplier);
Finally, if you think you'll need a number larger than Int32.MaxValue, you can use an Int64 (long), like this:
string inputString = "My Test String ~!##$%^&*()_+{}:<>?|"
int multiplier = 0;
long largeSum = 0;
foreach (char c in inputString)
{
largeSum += ((int)c) * ++multiplier;
}

How can I count the numbers in a string of mixed text/numbers

So what I'm trying to do, is take a job number, which looks like this xxx123432, and count the digits in the entry, but not the letters. I want to then assign the number of numbers to a variable, and use that variable to provide a check against the job numbers to determine if they are in a valid format.
I've already figured out how to perform the check, but I have no clue how to go about counting the numbers in the job number.
Thanks so much for your help.

Using LINQ :
var count = jobId.Count(x => Char.IsDigit(x));
or
var count = jobId.Count(Char.IsDigit);

int x = "xxx123432".Count(c => Char.IsNumber(c)); // 6
or
int x = "xxx123432".Count(c => Char.IsDigit(c)); // 6
The difference between these two methods see at Char.IsDigit and Char.IsNumber.

Something like this maybe?
string jobId = "xxx123432";
int digitsCount = 0;
foreach(char c in jobId)
{
if(Char.IsDigit(c))
digitsCount++;
}
And you could use LINQ, like this:
string jobId = "xxx123432";
int digitsCount = jobId.Count(c => char.IsDigit(c));

string str = "t12X234";
var reversed = str.Reverse().ToArray();
int digits = 0;
while (digits < str.Length &&
Char.IsDigit(reversed[digits])) digits++;
int num = Convert.ToInt32(str.Substring(str.Length - digits));
This gives num 234 as output if that is what you need.
The other linq/lambda variants just count characters which I think is not completely correct if you have a string like "B2B_MESSAGE_12344", because it would count the 2 in B2B.
But I'm not sure if I understood correctly what number of numbers means. Is it the count of numbers (other answers) or the number that numbers form (this answer).