C# 0 The Complete Reference

StartsWith( )

 returns true if the invoking string begins with the string passed in 

str.

EndsWith( )

 returns true if the invoking string ends with the string passed in 

str.

 Both 

return false on failure.

Here is a program that demonstrates several of the string search methods:

// Search strings.

using System;

class StringSearchDemo {

  static void Main() {

    string str = "C# has powerful string handling.";

    int idx;

    Console.WriteLine("str: " + str);

    idx = str.IndexOf('h');

    Console.WriteLine("Index of first 'h': " + idx);

www.freepdf-books.com

---

674

 

P a r t   I I :  

E x p l o r i n g   t h e   C #   L i b r a r y

    idx = str.LastIndexOf('h');

    Console.WriteLine("Index of last 'h': " + idx);

    idx = str.IndexOf("ing");

    Console.WriteLine("Index of first \"ing\": " + idx);

    idx = str.LastIndexOf("ing");

    Console.WriteLine("Index of last \"ing\": " + idx);

    char[] chrs = { 'a', 'b', 'c' };

    idx = str.IndexOfAny(chrs);

    Console.WriteLine("Index of first 'a', 'b', or 'c': " + idx);

    if(str.StartsWith("C# has"))

      Console.WriteLine("str begins with \"C# has\"");

    if(str.EndsWith("ling."))

      Console.WriteLine("str ends with \"ling.\"");

  }

}

The output from the program is shown here:

str: C# has powerful string handling.

Index of first 'h': 3

Index of last 'h': 23

Index of first "ing": 19

Index of last "ing": 28

Index of first 'a', 'b', or 'c': 4

str begins with "C# has"

str ends with "ling."

A string search method that you will find useful in many circumstances is 

Contains( )

.

Its general form is shown here:

public bool Contains(string 

str

)

It returns true if the invoking string contains the string specified by 

str

 and false otherwise. 

This method is especially useful when all you need to know is if a specific substring exists 

within another string. Here is an example that demonstrates its use:

// Demonstrate Contains().

using System;

class ContainsDemo {

  static void Main() {

    string str = "C# combines power with performance.";

    if(str.Contains("power"))

      Console.WriteLine("The sequence power was found.");

    if(str.Contains("pow"))

      Console.WriteLine("The sequence pow was found.");

www.freepdf-books.com

---