Meknowsnothing
New member
I'm learning C# programming on Linux Mint. I saw an exercise where one ask to find a string that its md5-hash starts like 314159265358. I was able to do the program that runs from command line and stops computing if one presses esc. But how can I modify the code such that it stops computing and saves results to the file whenever program closes, like one types command pkill from command line? I tried to ask the question in https://artofproblemsolving.com/com...sults_in_clinux_mint_when_one_stops_computing but got no answer. My code is at the moment the following:
C#:
using System;
using System.IO;
using System.Text;
//using StringBuilder;
// This is an exercise from [URL]https://www.ohjelmointiputka.net/postit/tehtava.php?tunnus=ssana2[/URL] .
// It tries to find an md5-hash that begins with hexadecimals 314159265...
namespace RandomCS
{
public class Program
{
public static void Main()
{
string md5 = "";
string last = "a";
string c = "";
string file = "md5piresults.txt";
string path = "/home/jaakko/Desktop/Programming/";
int limit = 1;
int cp = 0;
string bestsa;
string charstring;
string[] lines = System.IO.File.ReadAllLines(@path+file);
Console.WriteLine(lines[0]+"\n" +lines[1]);
const string pi = "314159265358";
do {
last = lines[0].Substring(6,lines[0].Length-6);
Console.WriteLine("We got: "+last);
bestsa = lines[1].Substring(6,lines[1].Length-6);
charstring = last;
cp = CommonPrefix(CreateMD5(bestsa),pi).Length;
Console.WriteLine("The best we have found = "+bestsa+", md5="+CreateMD5(bestsa)+ ",n="+cp);
limit = cp+1;
while (!Console.KeyAvailable) {
md5 = CreateMD5(charstring);
c = CommonPrefix(md5,pi);
if (c.Length >= limit) {
Console.WriteLine(charstring+" " +md5+ " " +c.Length);
lines[0] = "last: "+charstring;
lines[1] = "best: "+charstring;
System.IO.File.WriteAllLines(@path +file,lines);
Console.WriteLine("We saved to the file " +file + " lines " + lines[0] + " and "+lines[1]);
limit = c.Length + 1;
}
charstring = Increase(charstring);
if (charstring == endstring(charstring.Length)) {
md5 = CreateMD5(charstring);
c = CommonPrefix(md5,pi);
if (c.Length >= limit) {
Console.WriteLine(charstring+" " +md5+ " "+c.Length);
lines[0] = "last: "+charstring;
lines[1] = "best: "+charstring;
System.IO.File.WriteAllLines(@path +file,lines);
limit = c.Length + 1;
}
charstring = startstring(charstring.Length+1);
}
}
}
while (Console.ReadKey(true).Key != ConsoleKey.Escape);
string best = "";
lines[0] = "last: "+charstring;
md5 = CreateMD5(charstring);
c = CommonPrefix(md5,pi);
if (c.Length >= limit) {
best = charstring;
lines[1] = "best: "+best;
}
System.IO.File.WriteAllLines(@path +file,lines);
Console.WriteLine("We exit at the point "+charstring);
Console.WriteLine(charstring);
Console.WriteLine(limit);
}
// This is from [URL]https://stackoverflow.com/questions/33709165/get-common-prefix-of-two-string[/URL] .
public static string CommonPrefix(string a, string b)
{
if (a == null)
throw new ArgumentNullException(nameof(a));
if (b == null)
throw new ArgumentNullException(nameof(b));
var min = Math.Min(a.Length, b.Length);
var sb = new StringBuilder(min);
for (int i = 0; i < min && a[i] == b[i]; i++)
sb.Append(a[i]);
return sb.ToString();
}
private static string startstring(int n) {
string start = "";
for (int i=0; i<n; ++i) {
start += "a";
}
return start;
}
private static string endstring(int n) {
string end = "";
for (int i=0; i<n; ++i) {
end += "z";
}
return end;
}
// This is from [URL]https://stackoverflow.com/questions/11454004/calculate-a-md5-hash-from-a-string[/URL]
public static string CreateMD5(string input)
{
// Use input string to calculate MD5 hash
using (System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create())
{
byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
byte[] hashBytes = md5.ComputeHash(inputBytes);
// Convert the byte array to hexadecimal string
StringBuilder sb = new StringBuilder();
for (int i = 0; i < hashBytes.Length; i++)
{
sb.Append(hashBytes[i].ToString("X2"));
}
return sb.ToString();
}
}
// The idea is from [URL]https://artofproblemsolving.com/community/c163h1699980_how_to_find_the_next_string_in_c[/URL]
private static string Increase(string thing)
{
char[] charArray = thing.ToCharArray();
bool differentcharacter = false;
for (int i=0; i<charArray.Length; ++i) {
if (charArray[i]!= 'z') {
differentcharacter = true;
}
}
if (differentcharacter == false) {
return thing;
}
bool carry = false;
for (int i = charArray.Length - 1; i >= 0; i--)
{
char c = charArray[i];
if (carry)
{
if (c != 'z' && c != 'Z')
{
charArray[i] = ++c;
break;
}
charArray[i] = (char) (c - 25);
} else
{
if (c != 'z' && c != 'Z')
{
charArray[i] = (char) (c + 1);
break;
}
charArray[i] = (char) (c - 25);
carry = true;
}
}
return new String(charArray);
}
}
}
