First Non-Repeated Character from a UNICODE String using Hash Table
the only difference here is the input string can be UNICODE (65000 characters) instead of ASCII Code (256 characters) so using a hash table makes more sense
public static char FirstNonRepeatedHash(string stringToCheck)
{
Hashtable cHash = new Hashtable();
int length = stringToCheck.Length;
int i = 0;
bool hashPresent = false;
char charToReturn = '\0';
for (i = 0; i < length; i++)
{
hashPresent = cHash.Contains(stringToCheck[i]);
if (hashPresent)
{
cHash[stringToCheck[i]] = 1 + Convert.ToInt32(cHash[stringToCheck[i]]);
}
else
{
cHash.Add(Convert.ToChar(stringToCheck[i]), 1);
}
}
for (i = 0; i < length; i++)
{
if (Convert.ToInt32(cHash[stringToCheck[i]]) ==1 )
{
charToReturn = stringToCheck[i];
break;
}
}
return charToReturn;
}
Labels: CSharpTricks, String Manipulation
Monday, December 25, 2006
First Non repeated Character in a String using an Array
Here is how to find the first non repeated character in an a string using an arraythe assumption is the String is ASCII other wise check for the hash table function
For example If the input is "TEETOTALAR" The First non repeated Character is "O"
public static char FirstNonRepeatedArray(string stringToCheck)
{
int length = stringToCheck.Length;
int i = 0;
int[] intCollection = new int[256];
char returnChar = '\0';
for (i = 0; i < length; i++)
{
intCollection[stringToCheck[i]] = intCollection[stringToCheck[i]] + 1;
}
for (i = 0; i < length; i++)
{
if (intCollection[stringToCheck[i]] == 1)
{
returnChar = stringToCheck[i];
break;
}
}
return returnChar;
}
Labels: CSharpTricks, String Manipulation
String is a Palindrome !
How to check if a string is a palindrome ?You can change the code a bit to reverse an array
public static bool IsPalindrome(string s)
{
int length =s.Length;
char[] chrArray = s.ToCharArray();
if (length == 0)
return false;
if (length == 1)
return true;
int start = 0;
int end = length - 1;
while (end > start)
{
if (chrArray[start] == chrArray[end])
{
start++;
end--;
}
else
{
return false;
}
}
return true;
}
Labels: CSharpTricks, String Manipulation
Saturday, November 25, 2006
Remove Characters from a String with limited Memory
How about, If we don't have enough memory we have to use a single array.Here is how to do that with limited memory
public static string RemoveCharactersLimited(char[] s, string removeChars)
{
int i = 0, j = 0;
int lengthC = removeChars.Length;
int lengthS = s.Length;
int[] intCollection = new int[256];
for (i = 0; i < lengthC; i++)
{
intCollection[removeChars[i]] = 1;
}
i = j = 0;
for (i = 0; i < lengthS; i++)
{
if (intCollection[s[i]] != 1)
{
s[j] = s[i];
j++;
}
}
while (j < lengthS)
{
s[j] = '\0';
j++;
}
return new string(s);
}
Labels: CSharpTricks, String Manipulation
Wednesday, October 25, 2006
Remove Characters from String C#.NET
The string manipulation function removes a set of characters fromthe input stringFor example
Removing "RT" from "ROBERT FROST" will give you "OBE FOS"
public static string RemoveCharacters(string s, string removeChars)
{
int i=0,j=0;
int lengthC = removeChars.Length;
int lengthS = s.Length;
int[] intCollection = new int[256];
char[] s2 = new char[lengthS];
for (i = 0; i < lengthC; i++)
{
intCollection[removeChars[i]] = 1;
}
i = j = 0;
for (i = 0; i < lengthS; i++)
{
if (intCollection[s[i]] != 1)
{
s2[j] = s[i];
j++;
}
}
return new string(s2);
}
Labels: CSharpTricks, String Manipulation
AtoI function - String to Integer in C# .NET
If you ever want to convert a string to integer, you have to go through the following checks
public static int StringToInt(string s)
{
int length = s.Length;
int i = 0;
int lastNumber = 0;
int returnNumber = 0;
bool numberNegative = false;
int startPoint = 0;
if (s[0] == '-')
{
numberNegative = true;
startPoint = 1;
}
for (i = startPoint; i < length; i++)
{
if (s[i] == ' ')
{
continue;
}
else
{
if ((s[i] >= '0') && s[i] <= '9')
{
returnNumber = s[i] - '0';
if (i > 0) lastNumber = lastNumber * 10;
lastNumber = lastNumber + returnNumber;
}
else
{
break;
}
}
}
if (numberNegative)
lastNumber = -1 * lastNumber;
return lastNumber;
}
Labels: CSharpTricks, String Manipulation
Monday, September 25, 2006
Reverse Words in C Sharp.NET
Lately I started some string manipulation in C Sharp, which you will see in the series to come. Please add your comments suggestions. These are optimized for performanceInput: Robert Frost
output is Frost Robert
public static string ReverseWord(string s)
{
int length = s.Length;
int i = 0;
string[] splittedArray = s.Split(' ');
StringBuilder sb = new StringBuilder();
for (i = splittedArray.Length - 1; i >= 0; i--)
{
if (i != 0)
sb.Append(splittedArray[i] + ' ');
else
sb.Append(splittedArray[i]);
}
return sb.ToString();
}
Here is another method to do the same using character array
public static string ReverseWordChar(string s)
{
int length = s.Length;
int i = 0,j=0;
StringBuilder sb= new StringBuilder();
int startPos = length - 1;
for (i = length-1; i >=0;i--)
{
if (s[i] == ' ')
{
for (j = i+1; j <= startPos; j++)
{
sb.Append(s[j]);
}
startPos = i;
sb.Append(' ');
}
}
for (j = 0; j < startPos; j++)
{
sb.Append(s[j]);
}
return sb.ToString();
}
Labels: CSharpTricks, String Manipulation