C# String LastIndexOf(Char, Int32, Int32)

Description

String LastIndexOf(Char, Int32, Int32) reports the zero-based index position of the last occurrence of the specified Unicode character in a substring within this instance. The search starts at a specified character position and proceeds backward toward the beginning of the string for a specified number of character positions.

Syntax

String.LastIndexOf(Char, Int32, Int32) has the following syntax.

public int LastIndexOf(
  char value,/*  w  ww.  ja va2s  .  c o m*/
  int startIndex,
  int count
)

Parameters

String.LastIndexOf(Char, Int32, Int32) has the following parameters.

• value - The Unicode character to seek.
• startIndex - The starting position of the search. The search proceeds from startIndex toward the beginning of this instance.
• count - The number of character positions to examine.

Returns

String.LastIndexOf(Char, Int32, Int32) method returns The zero-based index position of value if that character is found, or -1 if it is not found or if the current instance equals String.Empty.

Example

Sample for String.LastIndexOf(Char, Int32, Int32)

//from   w  w w  .  j av  a  2  s  .c o  m
using System;

class Sample {
    public static void Main() {
        string str = "this is a test.";
        int start = str.Length-1;
        int at = 0;
        int count = 0;
        int end = start/2 - 1;
        while((start > -1) && (at > -1)){
            count = start - end; //Count must be within the substring.
            at = str.LastIndexOf('t', start, count);
            if (at > -1) {
                Console.Write("{0} ", at);
                start = at - 1;
            }
        }
    }
}

The code above generates the following result.