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How to return the char, of a loops next position, in a char array?

I want to replace a string (that the user inputs) with the next character in the alphabet. I'm having trouble returning the next value from my loop.
Error message: Index was outside the bounds of the array.
I understand that the array ends, and that might be a problem from the +1 I entered. How would I go about solving this?
string inputString = "abcdefghijklmnopqqrstuvxyz";
char[] inputCharArray = inputString.ToCharArray();
char[] alphabetArray = "abcdefghijklmnopqrstuvxyz".ToArray();
var resultStr = "";
for (int i = 0; i < inputCharArray.Length; i++)
{
if(alphabetArray.Contains(inputCharArray[i]))
resultStr += inputCharArray[i+1];
else
resultStr += inputCharArray[i];
}
System.Console.WriteLine(resultStr);

You're getting an Out Of Range exception because i will eventually equal the last index of your input array, and adding 1 to that number is beyond what the array has.
First, make it easier on yourself by making a function to convert a single char into the next letter.
Note, this answer assumes that you want to "wrap around" - the next letter after "z" goes back to "a".
char NextLetter(char input)
{
if (input < 'a' || input > 'z') // simple validation
throw new ArgumentException();
input += (char)1; // go to the next char value
if (input > 'z') // did you go past z?
input = 'a'; // go back to a
return input;
}
Yes, you can also do modulo, this method is the simple version.
Now you can loop through all the letters in your input to construct the output string. In addition, you don't need to .ToCharArray() a string - a string already implements IEnumerable<char>.
var input = "abcxyz";
var outputBuilder = new StringBuilder();
foreach (char letter in input)
{
outputBuilder.Append(NextLetter(letter));
}
Console.WriteLine(outputBuilder.ToString());
// prints "bcdyza"

You can use Array.IndexOf to find the index of the current character in the alphabet, then you can use the modulo operator (%) to get the index of the next character in the alphabet (assuming the alphabet wraps from z to a in your desired solution):
string inputString = "abcdefghijklmnopqqrstuvxyz";
char[] inputCharArray = inputString.ToCharArray();
char[] alphabetArray = "abcdefghijklmnopqrstuvxyz".ToArray();
var resultStr = "";
for (var i = 0; i < inputCharArray.Length; i++)
{
var indexInAlphabet = Array.IndexOf(alphabetArray, inputCharArray[i]);
var indexOfNextLetter = (indexInAlphabet + 1) % alphabetArray.Length;
resultStr += alphabetArray[indexOfNextLetter];
}
Console.WriteLine(resultStr);

Iterating backwards through an char array after finding a known word

I've got a project I'm working on in C#. I've got two char array's. One is a sentence and one is a word. I've got to iterate through the sentence array until I find a word that matches the word that was turned into an word array what I'm wondering is once I find the word how do I iterate backwards through the sentence array at the point I found the word back through the same length as the word array?
Code :
String wordString = "(Four)";
String sentenceString = "Maybe the fowl of Uruguay repeaters (Four) will be found";
char[] wordArray = wordString.ToCharArray();
List<String> words = sentenceString.Split(' ').ToList<string>();
//This would be the part where I iterate through sentence
foreach (string sentence in sentArray)
{
//Here I would need to find where the string of (Four) and trim it and see if it equals the wordString.
if (sentence.Contains(wordString)
{
//At this point I would need to go back the length of wordString which happens to be four places but I'm not sure how to do this. And for each word I go back in the sentence I need to capture that in another string array.
}
I don't know if I'm being clear enough on this but if I'm not please feel free to ask.. Thank you in advanced. Also what this should return is "fowl of Uruguay repeaters". So basically the use case is for the number of letters in the parenthesis the logic should return the same number of words before the word in parenthesis.

our are you. I have few question concerned to this exercise.
If the Word (four) was in beginning it should not return? or return all string?
As the length of four is equal to 4 imagine if that word appear as the second word on sentence what it should return just the first word or return 4 words even including the (four) word.?
My solution is the laziest one I just see your question and decide to help.
My solution assumes it return all the word before the (four) if the length is bigger than the word before the (four) word.
My solution return empty string if the word (four) is in the beginning.
My solution return Length of (four) (4) words before (four) word.
ONCE AGAIN IT IS NOT MY BEST APPROACH.
I see the code bellow:
string wordString = "(Four)";
string sentenceString = "Maybe the fowl of Uruguay repeaters (Four) will be found";
//Additionally you can add splitoption to remove the empty word on split function bellow
//Just in case there are more space in sentence.
string[] splitedword = sentenceString.Split(' ');
int tempBackposition = 0;
int finalposition = 0;
for (int i = 0; i < splitedword.Length; i++)
{
if (splitedword[i].Contains(wordString))
{
finalposition = i;
break;
}
}
tempBackposition = finalposition - wordString.Replace("(","").Replace(")","").Length;
string output = "";
tempBackposition= tempBackposition<0?0:tempBackposition;
for (int i = tempBackposition; i < finalposition; i++)
{
output += splitedword[i] + " ";
}
Console.WriteLine(output);
Console.ReadLine();
If it's not what you want can you answer my questions on top? or help me to understand were it's wrong

int i ;
string outputString = (i=sentenceString.IndexOf(wordString))<0 ?
sentenceString : sentenceString.Substring(0,i) ;

var wordString = "(Four)";
int wordStringInt = 4; // Just do switch case to convert your string to int
var sentenceString = "Maybe the fowl of Uruguay repeaters (Four) will be found";
var sentenceStringArray = sentenceString.Split(' ').ToList();
int wordStringIndexInArray = sentenceStringArray.IndexOf(wordString) - 1;
var stringOutPut = "";
if (wordStringIndexInArray > 0 && wordStringIndexInArray > wordStringInt)
{
stringOutPut = "";
while (wordStringInt > 0)
{
stringOutPut = sentenceStringArray[wordStringInt] + " " + stringOutPut;
wordStringInt--;
}
}

What you are matching is kind of complex, so for a more general solution you could use regular expressions.
First we declare what we are searching for:
string word = "(Four)";
string sentence = "Maybe the fowl of Uruguay repeaters (Four) will be found";
We will then search for the words in this string using regular expressions. Since we don't want to match whitespace, and we need to know where each match actually starts and we need to know the word inside the parenthesis we tell it that we optionally want opening and ending parenthesis, but we also want the contents of those as a match:
var words = Regex.Matches(sentence, #"[\p{Ps}]*(?<Content>[\w]+)[\p{Pe}]*").Cast<Match>().ToList();
[\p{Ps}] means we want opening punctuation ([{ etc. while the * indicates zero or more.
Followed is a sub-capture called Content (specified by ?<Content>) with one or more word characters.
At the end we specify that we want zero or more ending punctuation.
We then need to find the word in the list of matches:
var item = words.Single(x => x.Value == word);
Then we need to find this item's index:
int index = words.IndexOf(item);
At this point we just need to know the length of the contents:
var length = item.Groups["Content"].Length;
This length we use to go back in the string 4 words
var start = words.Skip(index - length).First();
And now we have everything we need:
var result = sentence.Substring(start.Index, item.Index - start.Index);
Result should contain fowl of Uruguay repeaters.
edit: It may be a lot simpler to just figure out the count from the word rather than from the content. In that case the complete code should be the following:
string word = "(Four)";
string sentence = "Maybe the fowl of Uruguay repeaters (Four) will be found";
var wordMatch = Regex.Match(word, #"[\p{Ps}]*(?<Content>[\w]+)[\p{Pe}]*");
var length = wordMatch.Groups["Content"].Length;
var words = Regex.Matches(sentence, #"\S+").Cast<Match>().ToList();
var item = words.Single(x => x.Value == word);
int index = words.IndexOf(item);
var start = words.Skip(index - length).First();
var result = sentence.Substring(start.Index, item.Index - start.Index);
\S+ in this case means "match one or more non-whitespace character".

You should try something like the following, which uses Array.Copy after it finds the number word. You will still have to implement the ConvertToNum function correctly (it is hardcoded in for now), but this should be a quick and easy solution.
string[] GetWords()
{
string sentenceString = "Maybe the fowl of Uruguay repeaters (Four) will be found";
string[] words = sentenceString.Split();
int num = 0;
int i; // scope of i should remain outside the for loop
for (i = 0; i < words.Length; i++)
{
string word = words[i];
if (word.StartsWith("(") && word.EndsWith(")"))
{
num = ConvertToNum(word.Substring(1, word.Length - 1));
// converted the number word we found, so we break
break;
}
}
if (num == 0)
{
// no number word was found in the string - return empty array
return new string[0];
}
// do some extra checking if number word exceeds number of previous words
int startIndex = i - num;
// if it does - just start from index 0
startIndex = startIndex < 0 ? 0 : startIndex;
int length = i - startIndex;
string[] output = new string[length];
Array.Copy(words, startIndex, output, 0, length);
return output;
}
// Convert the number word to an integer
int ConvertToNum(string numberStr)
{
return 4; // you should implement this method correctly
}
See - Convert words (string) to Int, for help implementing the ConvertToNum solution. Obviously it could be simplified depending on the range of numbers you expect to deal with.

Here is my solution, im not using regex at all, for the sake of easy understanding:
static void Main() {
var wordString = "(Four)";
int wordStringLength = wordString.Replace("(","").Replace(")","").Length;
//4, because i'm assuming '(' and ')' doesn't count.
var sentenceString = "Maybe the fowl of Uruguay repeaters (Four) will be found";
//Transform into a list of words, ToList() to future use of IndexOf Method
var sentenceStringWords = sentenceString.Split(' ').ToList();
//Find the index of the word in the list of words
int wordIndex = sentenceStringWords.IndexOf(wordString);
//Get a subrange from the original list of words, going back x Times the legnth of word (in this case 4),
var wordsToConcat = sentenceStringWords.GetRange(wordIndex-wordStringLength, wordStringLength);
//Finally concat the output;
var outPut = string.Join(" ", wordsToConcat);
//Output: fowl of Uruguay repeaters
}

I have a solution for you:
string wordToMatch = "(Four)";
string sentence = "Maybe the fowl of Uruguay repeaters (Four) will be found";
if (sentence.Contains(wordToMatch))
{
int length = wordToMatch.Trim(new[] { '(', ')' }).Length;
int indexOfMatchedWord = sentence.IndexOf(wordToMatch);
string subString1 = sentence.Substring(0, indexOfMatchedWord);
string[] words = subString1.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
var reversed = words.Reverse().Take(length);
string result = string.Join(" ", reversed.Reverse());
Console.WriteLine(result);
Console.ReadLine();
}
Likely this can be improved regardng performance, but I have a feeling you don't care about that. Make sure you are using 'System.Linq'

I assumed empty returns when input is incomplete, feel free to correct me on that. Wasn't 100% clear in your post how this should be handled.
private string getPartialSentence(string sentence, string word)
{
if (string.IsNullOrEmpty(sentence) || string.IsNullOrEmpty(word))
return string.Empty;
int locationInSentence = sentence.IndexOf(word, StringComparison.Ordinal);
if (locationInSentence == -1)
return string.Empty;
string partialSentence = sentence.Substring(0, locationInSentence);
string[] words = partialSentence.Split(new[] {' '}, StringSplitOptions.RemoveEmptyEntries);
int nbWordsRequired = word.Replace("(", "").Replace(")", "").Length;
if (words.Count() >= nbWordsRequired)
return String.Join(" ", words.Skip(words.Count() - nbWordsRequired));
return String.Join(" ", words);
}

I went with using an enumeration and associated dictionary to pair the "(Four)" type strings with their integer values. You could just as easily (and maybe easier) go with a switch statement using
case "(Four)": { currentNumber = 4; };
I feel like the enum allows a little more flexibility though.
public enum NumberVerb
{
one = 1,
two = 2,
three = 3,
four = 4,
five = 5,
six = 6,
seven = 7,
eight = 8,
nine = 9,
ten = 10,
};
public static Dictionary<string, NumberVerb> m_Dictionary
{
get
{
Dictionary<string, NumberVerb> temp = new Dictionary<string, NumberVerb>();
temp.Add("(one)", NumberVerb.one);
temp.Add("(two)", NumberVerb.two);
temp.Add("(three)", NumberVerb.three);
temp.Add("(four)", NumberVerb.four);
temp.Add("(five)", NumberVerb.five);
temp.Add("(six)", NumberVerb.six);
temp.Add("(seven)", NumberVerb.seven);
temp.Add("(eight)", NumberVerb.eight);
temp.Add("(nine)", NumberVerb.nine);
temp.Add("(ten)", NumberVerb.ten);
return temp;
}
}
static void Main(string[] args)
{
string resultPhrase = "";
// Get the sentance that will be searched.
Console.WriteLine("Please enter the starting sentance:");
Console.WriteLine("(don't forget your keyword: ie '(Four)')");
string sentance = Console.ReadLine();
// Get the search word.
Console.WriteLine("Please enter the search keyword:");
string keyword = Console.ReadLine();
// Set the associated number of words to backwards-iterate.
int currentNumber = -1;
try
{
currentNumber = (int)m_Dictionary[keyword.ToLower()];
}
catch(KeyNotFoundException ex)
{
Console.WriteLine("The provided keyword was not found in the dictionary.");
}
// Search the sentance string for the keyword, and get the starting index.
Console.WriteLine("Searching for phrase...");
string[] words = sentance.Split(' ');
int searchResultIndex = -1;
for (int i = 0; (searchResultIndex == -1 && i < words.Length); i++)
{
if (words[i].Equals(keyword))
{
searchResultIndex = i;
}
}
// Handle the search results.
if (searchResultIndex == -1)
{
resultPhrase = "The keyword was not found.";
}
else if (searchResultIndex < currentNumber)
{
// Check the array boundaries with the given indexes.
resultPhrase = "Error: Out of bounds!";
}
else
{
// Get the preceding words.
for (int i = 0; i < currentNumber; i++)
{
resultPhrase = string.Format(" {0}{1}", words[searchResultIndex - 1 - i], resultPhrase);
}
}
// Display the preceding words.
Console.WriteLine(resultPhrase.Trim());
// Exit.
Console.ReadLine();
}

Remove set of elements in an char array

I have a char array where I have to remove the elements from the same if I find the certain char. For eg: "paragraphs" is assigned in an char array. I have given search keyword as 'g'. If it is found then I have to remodify the original char array as "raphs" by removing all elements including the found one.
char[] ch = "paragraphs"
search chr = 'g'
Desired result(if chr found):
char[] ch = "raphs"
To explain bit clearer
I have to write a func. to find whether str(user input) contains all the char of the word "abcdef" in the same sequence as specify in the "abcdef". Return True if contains all the char in the same sequence or else false.
User Input: fgajbdcmdgeoplfqz
Output: true
User Input: asrbcyufde
Output: false

You can use LINQ's SkipWhile, which will skip elements until the search character is found.
An additionnal Skip is necessary to obtain raphs instead of graphs, and the ToArray() for the input string and result because you want to work with arrays.
char[] ch = "paragraphs".ToArray();
char search = 'g';
ch = ch.SkipWhile(c => c != search).Skip(1).ToArray(); // raphs
But honestly since your input is a string, I'd work with that:
string ch = "paragraphs";
char search = 'g';
ch = ch.Substring(ch.IndexOf(search) + 1);
and, if really necessary, convert it with .ToArray() afterwards.
And now to answer your 'clarification' (which is pretty much an other question by the way).
There are probably better ways to do it, but here's something that will accomplish what you want in O(n)
private bool ContainsInSequence(string input, string substring)
{
int substringIndex = 0;
for (int i = 0; i < input.Count(); i++)
{
if (input[i] == substring[substringIndex])
{
substringIndex++;
if (substringIndex == substring.Length)
{
return true;
}
}
}
return false;
}
Basically, you go through the input string in order, and each time you encounter the current letter from your substring you move to the next one.
When you reach the end of the substring, you know the input string contained all your substring, so you return true.
If we're not at the end after going through all the input this means there was a letter either out of order or missing, so we return false.
ContainsInSequence("fgajbdcmdgeoplfqz", "abcdef"); // true
ContainsInSequence("asrbcyufde ", "abcdef"); // false
ContainsInSequence("abcdfe", "abcdef"); // false

Try
char[] ch = "paragraphs".ToCharArray();
int index = Array.IndexOf(ch, 'g');
char[] result = new string(ch).Substring(index+1).ToCharArray();

Here's my version without using Linq:
static void Main(string[] args)
{
Console.WriteLine("Please provide a list of characters");
string Charactersinput = Console.ReadLine();
Console.WriteLine("Please provide the search character");
char Searchinput = Console.ReadKey().KeyChar;
Console.WriteLine("");
List<char> ListOfCharacters = new List<char>();
//fill the list of characters with the characters from the string
// Or empty it, if th esearch charcter is found
for (int i = 0; i < Charactersinput .Length; i++)
{
if (Searchinput == Charactersinput[i])
{
ListOfCharacters.Clear();
}
else
ListOfCharacters.Add(Charactersinput [i]);
}
//get your string back together
string Result = String.Concat(ListOfCharacters);
Console.WriteLine("Here's a list of all characters after processing: {0}", Result);
Console.ReadLine();
}

To answer your "clarification" question, which is very different from the original question:
I have to write a func. to find whether str(user input) contains all
the char of the word "abcdef" in the same sequence as specify in the
"abcdef". Return true if contains all the char in the same sequence or
else false.
Input: fgajbdcmdgeoplfqz Output: true
Input: asrbcyufde Output: false
The following function takes in two strings, a source string to search and a string containing the sequence of characters to match. It then searches through the source string, looking for each character (starting at the found position of the previous character). If any character is not found, it returns false. Otherwise it returns true:
public static bool ContainsAllCharactersInSameSequence(string sourceString,
string characterSequence)
{
// Short-circuit argument check
if (sourceString == null) return characterSequence == null;
if (characterSequence == null) return false;
if (characterSequence.Length > sourceString.Length) return false;
if (sourceString == characterSequence) return true;
int startIndex = 0;
foreach (char character in characterSequence)
{
int charIndex = sourceString.IndexOf(character, startIndex);
if (charIndex == -1) return false;
startIndex = charIndex + 1;
}
return true;
}

Split string after specific character or after max length

i want to split a string the following way:
string s = "012345678x0123x01234567890123456789";
s.SplitString("x",10);
should be split into
012345678
x0123
x012345678
9012345678
9
e.g. the inputstring should be split after the character "x" or length 10 - what comes first.
here is what i've tried so far:
public static IEnumerable<string> SplitString(this string sInput, string search, int maxlength)
{
int index = Math.Min(sInput.IndexOf(search), maxlength);
int start = 0;
while (index != -1)
{
yield return sInput.Substring(start, index-start);
start = index;
index = Math.Min(sInput.IndexOf(search,start), maxlength);
}
}

I would go with this regular expression:
([^x]{1,10})|(x[^x]{1,9})
which means:
Match at most 10 characters that are not x OR match x followed by at most 9 characters thar are not x
Here is working example:
string regex = "([^x]{1,10})|(x[^x]{1,9})";
string input = "012345678x0123x01234567890123456789";
var results = Regex.Matches(input, regex)
.Cast<Match>()
.Select(m => m.Value);
which produces values by you.

Personally I don't like RegEx. It creates code that is hard to de-bug and is very hard to work out what it is meant to be doing when you first look at it. So for a more lengthy solution I would go with something like this.
public static IEnumerable<string> SplitString(this string sInput, char search, int maxlength)
{
var result = new List<string>();
var count = 0;
var lastSplit = 0;
foreach (char c in sInput)
{
if (c == search || count - lastSplit == maxlength)
{
result.Add(sInput.Substring(lastSplit, count - lastSplit));
lastSplit = count;
}
count ++;
}
result.Add(sInput.Substring(lastSplit, count - lastSplit));
return result;
}
Note I changed the first parameter to a char (from a string). This code can probably be optimised some more, but it is nice and readable, which for me is more important.

Replace consecutive characters with same single character

I was just wondering if there is a simple way of doing this. i.e. Replacing the occurrence of consecutive characters with the same character.
For eg: - if my string is "something likeeeee tttthhiiissss" then my final output should be "something like this".
The string can contain special characters too including space.
Can you guys suggest some simple way for doing this.

This should do it:
var regex = new Regex("(.)\\1+");
var str = "something likeeeee!! tttthhiiissss";
Console.WriteLine(regex.Replace(str, "$1")); // something like! this
The regex will match any character (.) and \\1+ will match whatever was captured in the first group.

string myString = "something likeeeee tttthhiiissss";
char prevChar = '';
StringBuilder sb = new StringBuilder();
foreach (char chr in myString)
{
if (chr != prevChar) {
sb.Append(chr);
prevChar = chr;
}
}

How about:
s = new string(s
.Select((x, i) => new { x, i })
.Where(x => x.i == s.Length - 1 || s[x.i + 1] != x.x)
.Select(x => x.x)
.ToArray());
In english, we are creating a new string based on a char[] array. We construct that char[] array by applying a few LINQ operators:
Select: Capture the index i along with the current character x.
Filter out charaters that are not the same as the subsequent character
Select the character x.x back out of the anonymous type x.
Convert back to a char[] array so we can pass to constructor of string.

Console.WriteLine("Enter any string");
string str1, result="", str = Console.ReadLine();
char [] array= str.ToCharArray();
int i=0;
for (i = 0; i < str.Length;i++ )
{
if ((i != (str.Length - 1)))
{ if (array[i] == array[i + 1])
{
str1 = str.Trim(array[i]);
}
else
{
result += array[i];
}
}
else
{
result += array[i];
}
}
Console.WriteLine(result);
In this code the program ;
will read the string as entered from user
2.Convert the string in char Array using string.ToChar()
The loop will run for each character in string
each character stored in that particular position in array will be compared to the character stored in position one greater than that . And if the characters are found same the character stored in that particular array would be trimmed using .ToTrim()
For last character the loop will show error of index out of bound as it would be the last position value of the array. That's why I used * if ((i != (str.Length - 1)))*
6.The characters left after trimming are stored in result in concatenated form .

word = "something likeeeee tttthhiiissss"
re.sub(r"(.)\1+", r"\1",word)