About the-C # string reversal methods and comparison of performance C # string reversal methods and Performance Comparison

Original article: C # string reversal methods and Performance Comparison

 
I think it is strange when I see it. In many cases, the class library method must have better performance than the method I wrote.
 

 
The string input by the original author. If it is an array of input characters, the test result is much more unexpected.
ModifyCodeAs follows:
 

Class stringreverse {// <summary> // string reversal-stringbuilder implementation /// </Summary> /// <Param name = "str"> </param>/ // <returns> </returns> Public static string reverseusingstringbuilder (char [] Str) {int length = Str. length; stringbuilder sb = new stringbuilder (length); For (INT I = length-1; I> = 0; I --) {sb. append (STR [I]);} return sb. tostring ();} /// <summary> // string reversal-chararray implementation /// </Summary> /// <Param name = "str"> </param> // <returns> </returns> Public static string reverseusingchararray (char [] Str) {char [] arr = STR; array. reverse (ARR); return new string (ARR); // return string. join (string. empty, str. reverse ());} /// <summary> /// reverse string-XOR or implementation /// </Summary> /// <Param name = "str"> </param> /// <returns> </returns> Public static string reverseusingxor (char [] Str) {char [] arr = STR; int L = arr. length-1; // exchange value for (INT I = 0; I <L; I ++, l --) {STR [I] ^ = STR [l]; STR [l] ^ = STR [I]; STR [I] ^ = STR [l];} return new string (STR );} public Delegate string funcdelegate (char [] S ); /// <summary> /// test method /// </Summary> /// <Param name = "Description"> method description </param> /// <Param name = "func"> test method </param> /// <Param name = "times"> Number of executions </param> /// <Param name = "str"> test string </param> Public static void benchmark (string description, funcdelegate func, int times, char [] Str) {stopwatch Sw = new stopwatch (); Sw. start (); For (Int J = 0; j <times; j ++) {func (STR);} SW. stop (); console. writeline ("method {0}: Call {1} Times, in use {2 }. ", description, times, SW. elapsedticks );} /// <summary> /// generate a random string of the specified length /// </Summary> /// <Param name = "length"> length of the string </param>/ // <returns> </returns> Public static char [] randomstring (INT length) {random = new random (); // stringbuilder sb = new stringbuilder (); char [] sb = new char [length]; for (INT I = 0; I <length; I ++) {Sb [I] = convert. tochar (convert. toint32 (math. floor (26 * random. nextdouble () + 65);} return sb;} static void main (string [] ARGs) {int [] lengths = new int [] {1, 10, 15, 25, 50, 75,100,100 0, 100000}; // int [] lengths = new int [] {1, 10, 15, 25, 50, 75,100 }; foreach (INT Len in lengths) {// each method is executed 10000 times, and INT iterations = 10000 is precise; // generate a random test string char [] teststring = stringreverse. randomstring (LEN); // print the test information stringreverse. benchmark (string. format ("string Builder (test string length: {0})", Len), stringreverse. reverseusingstringbuilder, iterations, teststring); stringreverse. benchmark (string. format ("array. reverse (test string length: {0}) ", Len), stringreverse. reverseusingchararray, iterations, teststring); stringreverse. benchmark (string. format ("XOR (test string length: {0})", Len), stringreverse. reverseusingxor, iterations, teststring); console. writeline ();} console. read ();}}

Test results: