Controlling Output Manually in C#

Paint Code 39 Full ASCII in C# Controlling Output Manually

You often face the problem of breaking up a string or inserting some substring into the middle of another Replacing one character with another is most easily handled with the Replace() method, like this:

string s = Danger NoSmoking ; s = sReplace( , ! )

This example converts the string into Danger!NoSmoking Replacing all appearances of one character (in this case, a space) with another (an exclamation mark) is especially useful when generating commaseparated strings for easier parsing However, the more common and more difficult case involves breaking a single string into substrings, manipulating them separately, and then recombining them into a single, modified string The following RemoveWhiteSpace sample program uses the Replace() method to remove white space (spaces, tabs, and newlines all instances of a set of special characters) from a string:

// RemoveWhiteSpace -- Remove any of a set of chars from a given string // Use this method to remove whitespace from a sample string namespace RemoveWhiteSpace { using System; public class Program { public static void Main(string[] args) { // Define the white space characters char[] whiteSpace = { , \n , \t }; // Start with a string embedded with whitespace string s = this is a\nstring ; // Contains spaces & newline ConsoleWriteLine( before: + s); // Output the string with the whitespace missing ConsoleWrite( after: ); // Start looking for the white space characters for(;;) { // Find the offset of the character; exit the loop // if there are no more int offset = sIndexOfAny(whiteSpace); if (offset == -1) { break; } // Break the string into the part prior to the // character and the part after the character string before = sSubstring(0, offset); string after = sSubstring(offset + 1); // Now put the two substrings back together with the // character in the middle missing s = StringConcat(before, after); // Loop back up to find next whitespace char in // this modified s }

ConsoleWriteLine(s); // Wait for user to acknowledge the results ConsoleWriteLine( Press Enter to terminate ); ConsoleRead(); } } }

The key to this program is the boldfaced loop This loop continually refines a string consisting of the input string, s, removing every one of a set of characters contained in the array whiteSpace The loop uses IndexOfAny() to find the first occurrence of any of the chars in the whiteSpace array It doesn t return until every instance of any of those chars has been removed The IndexOfAny() method returns the index within the array of the first white space char that it can find A return value of 1 indicates that no items in the array were found in the string The first pass through the loop removes the leading blank on the target string IndexOfAny() finds the blank at index 0 The first Substring() call returns an empty string, and the second call returns the whole string after the blank These are then concatenated with Concat(), producing a string with the leading blank squeezed out The second pass through the loop finds the space after this and squeezes that out the same way, concatenating the strings this and is a\nstring After this pass, s has become thisis a\nstring The third pass finds the \n character and squeezes that out On the fourth pass, IndexOfAny() runs out of white space characters to find and returns 1 (not found) That ends the loop The RemoveWhiteSpace program prints out a string containing several forms of white space The program then strips out white space characters The output from this program appears as follows:

The RemoveWhiteSpace program demonstrates the use of the Concat() and IndexOf() methods; however, it doesn t use the most efficient approach As usual, a little examination reveals a more efficient approach using our old friend Split() You can find the program containing this code now in another example of a method on the Web site under RemoveWhiteSpaceWithSplit The method that does the work is shown here: