The number of times the specified character appears in the search string in C #.

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Using System;

Using System. Collections. Generic;

Using System. Linq;

Using System. Text;

Namespace StringOperate

{

/// <Summary>

/// String operation class

/// </Summary>

Class StrOperate

{

Private static int count; // number of times

Public static int Count

{

Get {return StrOperate. count ;}

Set {StrOperate. count = value ;}

}

Private string strContent; // string

Public string StrContent

{

Get {return strContent ;}

Set {strContent = value ;}

}

Private char searchChar; // The characters to be queried

Public char SearchChar

{

Get {return searchChar ;}

Set {searchChar = value ;}

}

/// <Summary>

/// Define the constructor and initialize the data

/// </Summary>

Public StrOperate (string strContent, char searchChar)

{

This. strContent = strContent;

This. searchChar = searchChar;

}

# Region // number of times a specified character appears in the query string

# Region method 1

/// <Summary>

/// In C #, a string is a character array,

/// Cyclically traverse each element in the character array,

/// Determine the number of times the specified Char appears

/// </Summary>

/// <Returns> specify the number of occurrences of a Char </returns>

Public int SearchCharCount_1 ()

{

Count = 0;

// Cyclically traverse each element (character) in string)

For (int I = 0; I <strContent. Length; I ++)

{

// Determine whether it is equal to the specified character

If (strContent [I] = searchChar)

{

// If the value is equal to, the number of times is increased by 1.

Count ++;

}

}

// Return times

Return count;

}

# Endregion

# Region method 2

/// <Summary>

/// Obtain the number of times through the IndexOf () function and Substring () function

/// </Summary>

/// <Returns> specify the number of occurrences of a Char </returns>

Public int SearchCharCount_2 ()

{

Count = 0;

String strCont = strContent;

While (true)

{

// Use the IndexOf () function to obtain the position where the specified character (searchChar) appears for the first time in the current string.

Int indexChar = strCont. IndexOf (searchChar );

// If the position is greater than or equal to 0, this character exists.

If (indexChar> = 0)

{

// Increase the number of times by 1

Count ++;

// String Update (use the Substring () function to extract the string that appears after the specified character for the next search)

StrCont = strCont. Substring (indexChar + 1 );

}

// Otherwise, if the position is smaller than 0, the current string does not contain any character to be searched.

Else

{

// End the loop

Break;

}

}

// Return times

Return count;

}

# Endregion

# Region method 3

/// <Summary>

/// Obtain the number of times through the Split () function

/// </Summary>

/// <Returns> specify the number of occurrences of a Char </returns>

Public int SearchCharCount_3 ()

{

Count = 0;

// Split the string according to the specified characters, so how many characters will be split)

String [] strs = strContent. Split (searchChar );

// For (int I = 0; I <strs. Length; I ++)

//{

// Console. WriteLine ("-" + strs [I] + "-");

//}

Count = strs. Length-1;

Console. WriteLine ("Lenght =" + strs. Length );

Return count;

}

# Endregion

# Region method 4

/// <Summary>

/// Obtain the number of times through the LastIndexOf () function and Substring () function

/// </Summary>

/// <Returns> specify the number of occurrences of a Char </returns>

Public int SearchCharCount_4 ()

{

Count = 0;

String strCont = strContent;

While (true)

{

// Use the IndexOf () function to obtain the position where the specified character (searchChar) appears for the first time in the current string.

Int indexChar = strCont. LastIndexOf (searchChar );

// If the position is greater than or equal to 0, this character exists.

If (indexChar> = 0)

{

// Increase the number of times by 1

Count ++;

// String Update (use the Substring () function to extract the string that appears after the specified character for the next search)

StrCont = strCont. Substring (0, indexChar );

}

// Otherwise, if the position is smaller than 0, the current string does not contain any character to be searched.

Else

{

// End the loop

Break;

}

}

// Return times

Return count;

}

# Endregion

# Region Method 5

/// <Summary>

/// Use the indexOf (), LastIndexOf (), and Substring () Functions

/// </Summary>

/// <Returns> specify the number of occurrences of a Char </returns>

Public int SearchCharCount_5 ()

{

Count = 0;

String strCont = strContent;

While (true)

{

Int indexof = strCont. IndexOf (searchChar );

Int lastIndexof = strCont. LastIndexOf (searchChar );

If (indexof! = LastIndexof)

{

Count + = 2;

StrCont = strCont. Substring (indexof + 1, lastIndexof-1-indexof );

// Bacdefa

// 0123456

}

Else

{

Break;

}

}

Return count;

}

# Endregion

# Region Method 6

/// <Summary>

/// Use string. ToArray () to convert the string into a character array.

/// </Summary>

/// <Returns> specify the number of occurrences of a Char </returns>

Public int SearchCharCount_6 ()

{

Count = 0;

Char [] chars = strContent. ToArray ();

For (int I = 0; I <chars. Length; I ++)

{

If (chars [I] = searchChar)

{

Count ++;

}

}

Return count;

}

# Endregion

# Endregion

}

}

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