// Count the number of characters matching the option.
public static int CountChars(string str, SeparateOptions option)
{
string found, notFound;
Separate(str, out found, out notFound, option);
return(found.Length);
}
// Separate characters from a string into two strings.
public static void Separate(string str, out string found, out string notFound, SeparateOptions option)
{
found = "";
notFound = "";
foreach (char ch in str)
{
switch (option)
{
case SeparateOptions.Digits:
if (char.IsDigit(ch))
{
found += ch;
}
else
{
notFound += ch;
}
break;
case SeparateOptions.Letters:
if (char.IsLower(ch) || char.IsUpper(ch))
{
found += ch;
}
else
{
notFound += ch;
}
break;
case SeparateOptions.Punctuation:
if (char.IsPunctuation(ch))
{
found += ch;
}
else
{
notFound += ch;
}
break;
case SeparateOptions.WhiteSpace:
if (char.IsWhiteSpace(ch))
{
found += ch;
}
else
{
notFound += ch;
}
break;
}
}
}