(转)交换两个指定位置字符的4种方法

方法一：

C# CODEstatic void Main()
        {
            string s = "123456789";
            SwapChar(ref s, 3, 6);
            Console.Write(s.ToString());
        }

        static void SwapChar(ref string s, int i1, int i2)
        {
            char temp = s[i1];
            char temp1 = s[i2];
            s = s.Remove(i1, 1).Insert(i1, temp1.ToString());
            s = s.Remove(i2, 1).Insert(i2, temp.ToString());
        }

方法二：

C# CODEstatic void Main()
        {
            string s = "123456789";
            //SwapChar(s, 3, 6);
            Console.Write(SwapChar(s, 3, 6).ToString());
        }

        static string SwapChar(string s, int p1, int p2)
        {
            if ((p1 == p2) || ((p1 < 0) || (p2 < 0))) return s;
            if ((p1 >= s.Length) || (p2 >= s.Length)) return s;
            char[] vChars = s.ToCharArray();
            vChars[p1] = (char)(vChars[p2] | (vChars[p2] = vChars[p1]) & 0);
            return new string(vChars);
        }

方法三：

C# CODEstatic void Main()
        {
            string s = "123456789";
            Console.Write(SwapChar(s, 3, 6).ToString());
        }

        public static string SwapChar(string str, int a, int b)
        {
            char[] newStr = str.ToCharArray();
            newStr[a] = str[b];
            newStr[b] = str[a];
            return new string(newStr);
        }

方法四：
C# CODE
using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;
namespace ConsoleApplication1
{
    class Program
    {
        static void Main()
        {
            string s = "123456789";
            Console.Write(SwapChar(s, 3, 6).ToString());
        }

        static string SwapChar(string s, int p1, int p2)
        {
            if (p1 > p2) ...{ int p = p1; p1 = p2; p2 = p; }
            return Regex.Replace(s, "^(.{" + p1 + "})(.)(.{" + (p2 - p1 - 1) + "})(.)(.*)$", "$1$4$3$2$5");
        }
    }
}