C++ md5算法？阶乘怎么算啊

调用:CMD5_VC::MD5(pBuf, nLength);CMD5_VC::MD5(fFile);CMD5_VC::MD5(strFilePath);原代码:// MD5Checksum.h: interface for the MD5Checksum class.////////////////////////////////////////////////////////////////////////#if !defined(AFX_MD5CHECKSUM_H__2BC7928E_4C15_11D3_B2EE_A4A60E20D2C3__INCLUDED_)#define AFX_MD5CHECKSUM_H__2BC7928E_4C15_11D3_B2EE_A4A60E20D2C3__INCLUDED_#if _MSC_VER 》 1000#pragma once#endif // _MSC_VER 》 1000class CMD5_VC{public: //interface functions for the RSA MD5 calculation static CString MD5(BYTE* pBuf, UINT nLength); static CString MD5(CFile& File); static CString MD5(const CString& strFilePath);protected: //constructor/destructor CMD5_VC(); virtual ~CMD5_VC() {}; //RSA MD5 implementation void Transform(BYTE Block); void Update(BYTE* Input, ULONG nInputLen); CString Final(); inline DWORD RotateLeft(DWORD x, int n); inline void FF( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T); inline void GG( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T); inline void HH( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T); inline void II( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T); //utility functions void DWordToByte(BYTE* Output, DWORD* Input, UINT nLength); void ByteToDWord(DWORD* Output, BYTE* Input, UINT nLength);private: BYTE m_lpszBuffer; //input buffer ULONG m_nCount; //number of bits, modulo 2^64 (lsb first) ULONG m_lMD5; //MD5 checksum};#endif // !defined(AFX_MD5CHECKSUM_H__2BC7928E_4C15_11D3_B2EE_A4A60E20D2C3__INCLUDED_)////////////////////////////////////////////////////////////////////////////////////Magic initialization constants#define MD5_INIT_STATE_0 0x67452301#define MD5_INIT_STATE_1 0xefcdab89#define MD5_INIT_STATE_2 0x98badcfe#define MD5_INIT_STATE_3 0x10325476//Constants for Transform routine.#define MD5_S11 7#define MD5_S12 12#define MD5_S13 17#define MD5_S14 22#define MD5_S21 5#define MD5_S22 9#define MD5_S23 14#define MD5_S24 20#define MD5_S31 4#define MD5_S32 11#define MD5_S33 16#define MD5_S34 23#define MD5_S41 6#define MD5_S42 10#define MD5_S43 15#define MD5_S44 21//Transformation Constants - Round 1#define MD5_T01 0xd76aa478 //Transformation Constant 1 #define MD5_T02 0xe8c7b756 // 2#define MD5_T03 0x242070db // 3#define MD5_T04 0xc1bdceee // 4#define MD5_T05 0xf57c0faf // 5#define MD5_T06 0x4787c62a // 6#define MD5_T07 0xa8304613 // 7#define MD5_T08 0xfd469501 // 8#define MD5_T09 0x698098d8 // 9#define MD5_T10 0x8b44f7af // 10#define MD5_T11 0xffff5bb1 // 11#define MD5_T12 0x895cd7be // 12#define MD5_T13 0x6b901122 // 13#define MD5_T14 0xfd987193 // 14#define MD5_T15 0xa679438e // 15#define MD5_T16 0x49b40821 // 16//s - Round 2#define MD5_T17 0xf61e2562 // 17#define MD5_T18 0xc040b340 // 18#define MD5_T19 0x265e5a51 // 19#define MD5_T20 0xe9b6c7aa // 20#define MD5_T21 0xd62f105d // 21#define MD5_T22 0x02441453 // 22#define MD5_T23 0xd8a1e681 // 23#define MD5_T24 0xe7d3fbc8 // 24#define MD5_T25 0x21e1cde6 // 25#define MD5_T26 0xc33707d6 // 26#define MD5_T27 0xf4d50d87 // 27#define MD5_T28 0x455a14ed // 28#define MD5_T29 0xa9e3e905 // 29#define MD5_T30 0xfcefa3f8 // 30#define MD5_T31 0x676f02d9 // 31#define MD5_T32 0x8d2a4c8a // 32//s - Round 3#define MD5_T33 0xfffa3942 // 33#define MD5_T34 0x8771f681 // 34#define MD5_T35 0x6d9d6122 // 35#define MD5_T36 0xfde5380c // 36#define MD5_T37 0xa4beea44 // 37#define MD5_T38 0x4bdecfa9 // 38#define MD5_T39 0xf6bb4b60 // 39#define MD5_T40 0xbebfbc70 // 40#define MD5_T41 0x289b7ec6 // 41#define MD5_T42 0xeaa127fa // 42#define MD5_T43 0xd4ef3085 // 43#define MD5_T44 0x04881d05 // 44#define MD5_T45 0xd9d4d039 // 45#define MD5_T46 0xe6db99e5 // 46#define MD5_T47 0x1fa27cf8 // 47#define MD5_T48 0xc4ac5665 // 48//s - Round 4#define MD5_T49 0xf4292244 // 49#define MD5_T50 0x432aff97 // 50#define MD5_T51 0xab9423a7 // 51#define MD5_T52 0xfc93a039 // 52#define MD5_T53 0x655b59c3 // 53#define MD5_T54 0x8f0ccc92 // 54#define MD5_T55 0xffeff47d // 55#define MD5_T56 0x85845dd1 // 56#define MD5_T57 0x6fa87e4f // 57#define MD5_T58 0xfe2ce6e0 // 58#define MD5_T59 0xa3014314 // 59#define MD5_T60 0x4e0811a1 // 60#define MD5_T61 0xf7537e82 // 61#define MD5_T62 0xbd3af235 // 62#define MD5_T63 0x2ad7d2bb // 63#define MD5_T64 0xeb86d391 // 64//Null data (except for first BYTE) used to finalise the checksum calculationstatic unsigned char PADDING = { 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};// MD5Checksum.cpp: implementation of the MD5Checksum class.////////////////////////////////////////////////////////////////////////#include “stdafx.h“#include “MD5_VC.h“#ifdef _DEBUG#undef THIS_FILEstatic char THIS_FILE=__FILE__;#define new DEBUG_NEW#endifCString CMD5_VC::MD5(const CString& strFilePath){ //open the file as a binary file in readonly mode, denying write access CFile File(strFilePath, CFile::modeRead | CFile::shareDenyWrite | CFile::typeBinary); //the file has been successfully opened, so now get and return its checksum return MD5(File);}CString CMD5_VC::MD5(CFile& File){ try { CMD5_VC MD5_VC; //MD5_VC object int nLength = 0; //number of bytes read from the file const int nBufferSize = 1024; //checksum the file in blocks of 1024 bytes BYTE Buffer[nBufferSize]; //buffer for data read from the file //checksum the file in blocks of 1024 bytes while ((nLength = File.Read( Buffer, nBufferSize )) 》 0 ) { MD5_VC.Update( Buffer, nLength ); } //finalise the checksum and return it return MD5_VC.Final(); } //report any file exceptions in debug mode only catch (CFileException* e ) { TRACE0(“CMD5_VC::MD5: CFileException caught“); throw e; }}CString CMD5_VC::MD5(BYTE* pBuf, UINT nLength){ //entry invariants AfxIsValidAddress(pBuf,nLength,FALSE); //calculate and return the checksum CMD5_VC MD5_VC; MD5_VC.Update( pBuf, nLength ); return MD5_VC.Final();}DWORD CMD5_VC::RotateLeft(DWORD x, int n){ //check that DWORD is 4 bytes long - true in Visual C++ 6 and 32 bit Windows ASSERT( sizeof(x) == 4 ); //rotate and return x return (x 《《 n) | (x 》》 (32-n));}void CMD5_VC::FF( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T){ DWORD F = (B & C) | (~B & D); A += F + X + T; A = RotateLeft(A, S); A += B;}void CMD5_VC::GG( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T){ DWORD G = (B & D) | (C & ~D); A += G + X + T; A = RotateLeft(A, S); A += B;}void CMD5_VC::HH( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T){ DWORD H = (B ^ C ^ D); A += H + X + T; A = RotateLeft(A, S); A += B;}void CMD5_VC::II( DWORD& A, DWORD B, DWORD C, DWORD D, DWORD X, DWORD S, DWORD T){ DWORD I = (C ^ (B | ~D)); A += I + X + T; A = RotateLeft(A, S); A += B;}void CMD5_VC::Transform(BYTE Block){ //initialise local data with current checksum ULONG a = m_lMD5; ULONG b = m_lMD5; ULONG c = m_lMD5; ULONG d = m_lMD5; //copy BYTES from input ’Block’ to an array of ULONGS ’X’ ULONG X; ByteToDWord( X, Block, 64 ); //Perform Round 1 of the transformation FF (a, b, c, d, X[ 0], MD5_S11, MD5_T01); FF (d, a, b, c, X[ 1], MD5_S12, MD5_T02); FF (c, d, a, b, X[ 2], MD5_S13, MD5_T03); FF (b, c, d, a, X[ 3], MD5_S14, MD5_T04); FF (a, b, c, d, X[ 4], MD5_S11, MD5_T05); FF (d, a, b, c, X[ 5], MD5_S12, MD5_T06); FF (c, d, a, b, X[ 6], MD5_S13, MD5_T07); FF (b, c, d, a, X[ 7], MD5_S14, MD5_T08); FF (a, b, c, d, X[ 8], MD5_S11, MD5_T09); FF (d, a, b, c, X[ 9], MD5_S12, MD5_T10); FF (c, d, a, b, X, MD5_S13, MD5_T11); FF (b, c, d, a, X, MD5_S14, MD5_T12); FF (a, b, c, d, X, MD5_S11, MD5_T13); FF (d, a, b, c, X, MD5_S12, MD5_T14); FF (c, d, a, b, X, MD5_S13, MD5_T15); FF (b, c, d, a, X, MD5_S14, MD5_T16); //Perform Round 2 of the transformation GG (a, b, c, d, X[ 1], MD5_S21, MD5_T17); GG (d, a, b, c, X[ 6], MD5_S22, MD5_T18); GG (c, d, a, b, X, MD5_S23, MD5_T19); GG (b, c, d, a, X[ 0], MD5_S24, MD5_T20); GG (a, b, c, d, X[ 5], MD5_S21, MD5_T21); GG (d, a, b, c, X, MD5_S22, MD5_T22); GG (c, d, a, b, X, MD5_S23, MD5_T23); GG (b, c, d, a, X[ 4], MD5_S24, MD5_T24); GG (a, b, c, d, X[ 9], MD5_S21, MD5_T25); GG (d, a, b, c, X, MD5_S22, MD5_T26); GG (c, d, a, b, X[ 3], MD5_S23, MD5_T27); GG (b, c, d, a, X[ 8], MD5_S24, MD5_T28); GG (a, b, c, d, X, MD5_S21, MD5_T29); GG (d, a, b, c, X[ 2], MD5_S22, MD5_T30); GG (c, d, a, b, X[ 7], MD5_S23, MD5_T31); GG (b, c, d, a, X, MD5_S24, MD5_T32); //Perform Round 3 of the transformation HH (a, b, c, d, X[ 5], MD5_S31, MD5_T33); HH (d, a, b, c, X[ 8], MD5_S32, MD5_T34); HH (c, d, a, b, X, MD5_S33, MD5_T35); HH (b, c, d, a, X, MD5_S34, MD5_T36); HH (a, b, c, d, X[ 1], MD5_S31, MD5_T37); HH (d, a, b, c, X[ 4], MD5_S32, MD5_T38); HH (c, d, a, b, X[ 7], MD5_S33, MD5_T39); HH (b, c, d, a, X, MD5_S34, MD5_T40); HH (a, b, c, d, X, MD5_S31, MD5_T41); HH (d, a, b, c, X[ 0], MD5_S32, MD5_T42); HH (c, d, a, b, X[ 3], MD5_S33, MD5_T43); HH (b, c, d, a, X[ 6], MD5_S34, MD5_T44); HH (a, b, c, d, X[ 9], MD5_S31, MD5_T45); HH (d, a, b, c, X, MD5_S32, MD5_T46); HH (c, d, a, b, X, MD5_S33, MD5_T47); HH (b, c, d, a, X[ 2], MD5_S34, MD5_T48); //Perform Round 4 of the transformation II (a, b, c, d, X[ 0], MD5_S41, MD5_T49); II (d, a, b, c, X[ 7], MD5_S42, MD5_T50); II (c, d, a, b, X, MD5_S43, MD5_T51); II (b, c, d, a, X[ 5], MD5_S44, MD5_T52); II (a, b, c, d, X, MD5_S41, MD5_T53); II (d, a, b, c, X[ 3], MD5_S42, MD5_T54); II (c, d, a, b, X, MD5_S43, MD5_T55); II (b, c, d, a, X[ 1], MD5_S44, MD5_T56); II (a, b, c, d, X[ 8], MD5_S41, MD5_T57); II (d, a, b, c, X, MD5_S42, MD5_T58); II (c, d, a, b, X[ 6], MD5_S43, MD5_T59); II (b, c, d, a, X, MD5_S44, MD5_T60); II (a, b, c, d, X[ 4], MD5_S41, MD5_T61); II (d, a, b, c, X, MD5_S42, MD5_T62); II (c, d, a, b, X[ 2], MD5_S43, MD5_T63); II (b, c, d, a, X[ 9], MD5_S44, MD5_T64); //add the transformed values to the current checksum m_lMD5 += a; m_lMD5 += b; m_lMD5 += c; m_lMD5 += d;}CMD5_VC::CMD5_VC(){ // zero members memset( m_lpszBuffer, 0, 64 ); m_nCount = m_nCount = 0; // Load magic state initialization constants m_lMD5 = MD5_INIT_STATE_0; m_lMD5 = MD5_INIT_STATE_1; m_lMD5 = MD5_INIT_STATE_2; m_lMD5 = MD5_INIT_STATE_3;}void CMD5_VC::ByteToDWord(DWORD* Output, BYTE* Input, UINT nLength){ //entry invariants ASSERT( nLength % 4 == 0 ); ASSERT( AfxIsValidAddress(Output, nLength/4, TRUE) ); ASSERT( AfxIsValidAddress(Input, nLength, FALSE) ); //initialisations UINT i=0; //index to Output array UINT j=0; //index to Input array //transfer the data by shifting and copying for ( ; j 《 nLength; i++, j += 4) { Output[i] = (ULONG)Input[j] | (ULONG)Input[j+1] 《《 8 | (ULONG)Input[j+2] 《《 16 | (ULONG)Input[j+3] 《《 24; }}void CMD5_VC::DWordToByte(BYTE* Output, DWORD* Input, UINT nLength ){ //entry invariants ASSERT( nLength % 4 == 0 ); ASSERT( AfxIsValidAddress(Output, nLength, TRUE) ); ASSERT( AfxIsValidAddress(Input, nLength/4, FALSE) ); //transfer the data by shifting and copying UINT i = 0; UINT j = 0; for ( ; j 《 nLength; i++, j += 4) { Output[j] = (UCHAR)(Input[i] & 0xff); Output[j+1] = (UCHAR)((Input[i] 》》 8) & 0xff); Output[j+2] = (UCHAR)((Input[i] 》》 16) & 0xff); Output[j+3] = (UCHAR)((Input[i] 》》 24) & 0xff); }}CString CMD5_VC::Final(){ //Save number of bits BYTE Bits; DWordToByte( Bits, m_nCount, 8 ); //Pad out to 56 mod 64. UINT nIndex = (UINT)((m_nCount 》》 3) & 0x3f); UINT nPadLen = (nIndex 《 56) ? (56 - nIndex) : (120 - nIndex); Update( PADDING, nPadLen ); //Append length (before padding) Update( Bits, 8 ); //Store final state in ’lpszMD5’ const int nMD5Size = 16; unsigned char lpszMD5[ nMD5Size ]; DWordToByte( lpszMD5, m_lMD5, nMD5Size ); //Convert the hexadecimal checksum to a CString CString strMD5; for ( int i=0; i 《 nMD5Size; i++) { CString Str; if (lpszMD5[i] == 0) { Str = CString(“00“); } else if (lpszMD5[i] 《= 15) { Str.Format(“0%X“,lpszMD5[i]); } else { Str.Format(“%X“,lpszMD5[i]); } ASSERT( Str.GetLength() == 2 ); strMD5 += Str; } ASSERT( strMD5.GetLength() == 32 ); return strMD5;}void CMD5_VC::Update( BYTE* Input, ULONG nInputLen ){ //Compute number of bytes mod 64 UINT nIndex = (UINT)((m_nCount 》》 3) & 0x3F); //Update number of bits if ( ( m_nCount += nInputLen 《《 3 ) 《 ( nInputLen 《《 3) ) { m_nCount++; } m_nCount += (nInputLen 》》 29); //Transform as many times as possible. UINT i=0; UINT nPartLen = 64 - nIndex; if (nInputLen 》= nPartLen) { memcpy( &m_lpszBuffer[nIndex], Input, nPartLen ); Transform( m_lpszBuffer ); for (i = nPartLen; i + 63 《 nInputLen; i += 64) { Transform( &Input[i] ); } nIndex = 0; } else { i = 0; } // Buffer remaining input memcpy( &m_lpszBuffer[nIndex], &Input[i], nInputLen-i);}

如果要精确计算阶乘，阶乘没有什么简便方法，只能一个一个的往下乘。这也是为何要专门用一个!来表示阶乘。如果只想计算大概的值，可以用“斯特林公式”（请自行百度）。其实想想也很自然，100!=1x2x3x...x10x11x12x...x20x21x...x99x100,从10以后，每乘一次，这个数就至少增加一位，所以这个数就是写出来，也至少是100位左右的数字，假设有的话，这个公式该多复杂。

用ga函数，ga函数就是遗传算法的函数，它的调用格式为：x=ga(fitnessfcn,nvars,a,b,aeq,beq,lb,ub,nonlcon,options)fitnessfcn就是待优化函数，nvars为变量个数，然后后面的lb是下界，ub是上界，你这个问题就需要这4个位置的参数，其他位置的参数用代替就行，由于ga函数默认是求待优化函数的最小值，所以要想求最大值需要把待优化函数取负，即编写为functiony=myfun(x)y=-x.*sin(10*pi.*x)-2;把这个函数存为myfun.m，然后在命令行里敲x=ga(@myfun,1,,,,,,)会返回optimizationterminated:averagechangeinthefitnessvaluelessthanoptions.tolfun.x=1.8506由于遗传算法的原理其实是在取值范围内随机选择初值然后进行遗传，所以可能每次运行给出的值都不一样，比如再运行一次会返回optimizationterminated:averagechangeinthefitnessvaluelessthanoptions.tolfun.x=1.6507这个具体原因需要参考遗传算法的有关资料