C++实现：把一个文件夹里的冗余文件(.txt)删除

代码很简单，调用了MFC里的几个函数。这里的冗余判断，是要遍历文件内容，进行两两比较。

需要注意的地方有两点：

1.源文件里头文件<afx.h>必须放在最前面。这里是为了避免nafxcwd.lib error LNK2005，由于CRT 库对 new、delete 和 DllMain 函数使用弱外部链接，MFC 库也包含 new、delete 和 DllMain 函数，这些函数要求先链接 MFC 库，然后再链接 CRT 库。

2.MFC库采取静态编译。这里是为了避免nafxcwd.lib error LNK2001。

代码实现：

#include <afx.h>
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

vector<CFileStatus> cf;
bool cmp(const CFileStatus &r1,const CFileStatus &r2){
    return r1.m_size<r2.m_size;
}

int main(){
    CFileFind finder;
    CFile cfile;
    CFileStatus rStatus;
    BOOL bWorking=finder.FindFile(_T("*.txt"));

    cout<<"正在搜索当前目录下冗余文件..."<<endl;
    while (bWorking){
        bWorking = finder.FindNextFile();
        CString fp = (LPCTSTR)finder.GetFilePath();
        CFile::GetStatus(fp,rStatus);
        cf.insert(cf.end(), rStatus);
    }
    sort(cf.begin(),cf.end(),cmp);
    for(int i=0;i < cf.size(); i++){
        int size = cf[i].m_size;
        int num = 0;
        bool tag = false;
        CFile file1(cf[i].m_szFullName,CFile::modeRead);
        char *FileContent1 = new char[cf[i].m_size];
        file1.Read(FileContent1,cf[i].m_size);
        for(int j=i+1;j < cf.size(); j++){
            if(cf[i].m_size == cf[j].m_size){
                CFile file2(cf[j].m_szFullName,CFile::modeRead);
                char *FileContent2 = new char[cf[j].m_size];
                file2.Read(FileContent2,cf[j].m_size);
                for(num =0; num <size; num++){
                    if(FileContent1[num] != FileContent2[num]){
                        break;
                    }
                }
                file2.Close();
                if(num == size){
                    cout<<"找到一组冗余文件，正在删除其中冗余文件! "<<endl;
                    file2.Remove(cf[j].m_szFullName);
                    cf.erase(cf.begin()+j);
                    j--;
                    delete FileContent2;
                }
            }else break;
            file1.Close();
        }
    }
    cout<<"已完成操作！"<<endl;
    return 0;
}

下面是加了MD5的版本(采取多文件组织)：

md5.h:

#ifndef MD5_H
#define MD5_H
 
typedef struct
{
    unsigned int count[2];
    unsigned int state[4];
    unsigned char buffer[64];   
}MD5_CTX;
 
                         
#define F(x,y,z) ((x & y) | (~x & z))
#define G(x,y,z) ((x & z) | (y & ~z))
#define H(x,y,z) (x^y^z)
#define I(x,y,z) (y ^ (x | ~z))
#define ROTATE_LEFT(x,n) ((x << n) | (x >> (32-n)))
#define FF(a,b,c,d,x,s,ac) 
          { 
          a += F(b,c,d) + x + ac; 
          a = ROTATE_LEFT(a,s); 
          a += b; 
          }
#define GG(a,b,c,d,x,s,ac) 
          { 
          a += G(b,c,d) + x + ac; 
          a = ROTATE_LEFT(a,s); 
          a += b; 
          }
#define HH(a,b,c,d,x,s,ac) 
          { 
          a += H(b,c,d) + x + ac; 
          a = ROTATE_LEFT(a,s); 
          a += b; 
          }
#define II(a,b,c,d,x,s,ac) 
          { 
          a += I(b,c,d) + x + ac; 
          a = ROTATE_LEFT(a,s); 
          a += b; 
          }                                            
void MD5Init(MD5_CTX *context);
void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen);
void MD5Final(MD5_CTX *context,unsigned char digest[16]);
void MD5Transform(unsigned int state[4],unsigned char block[64]);
void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len);
void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len);
 
#endif

md5.cpp:

#include <memory.h>
#include "md5.h"
 
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};
                         
void MD5Init(MD5_CTX *context)
{
     context->count[0] = 0;
     context->count[1] = 0;
     context->state[0] = 0x67452301;
     context->state[1] = 0xEFCDAB89;
     context->state[2] = 0x98BADCFE;
     context->state[3] = 0x10325476;
}
void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen)
{
    unsigned int i = 0,index = 0,partlen = 0;
    index = (context->count[0] >> 3) & 0x3F;
    partlen = 64 - index;
    context->count[0] += inputlen << 3;
    if(context->count[0] < (inputlen << 3))
       context->count[1]++;
    context->count[1] += inputlen >> 29;
    
    if(inputlen >= partlen)
    {
       memcpy(&context->buffer[index],input,partlen);
       MD5Transform(context->state,context->buffer);
       for(i = partlen;i+64 <= inputlen;i+=64)
           MD5Transform(context->state,&input[i]);
       index = 0;        
    }  
    else
    {
        i = 0;
    }
    memcpy(&context->buffer[index],&input[i],inputlen-i);
}
void MD5Final(MD5_CTX *context,unsigned char digest[16])
{
    unsigned int index = 0,padlen = 0;
    unsigned char bits[8];
    index = (context->count[0] >> 3) & 0x3F;
    padlen = (index < 56)?(56-index):(120-index);
    MD5Encode(bits,context->count,8);
    MD5Update(context,PADDING,padlen);
    MD5Update(context,bits,8);
    MD5Encode(digest,context->state,16);
}
void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len)
{
    unsigned int i = 0,j = 0;
    while(j < len)
    {
         output[j] = input[i] & 0xFF;  
         output[j+1] = (input[i] >> 8) & 0xFF;
         output[j+2] = (input[i] >> 16) & 0xFF;
         output[j+3] = (input[i] >> 24) & 0xFF;
         i++;
         j+=4;
    }
}
void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len)
{
     unsigned int i = 0,j = 0;
     while(j < len)
     {
           output[i] = (input[j]) |
                       (input[j+1] << 8) |
                       (input[j+2] << 16) |
                       (input[j+3] << 24);
           i++;
           j+=4; 
     }
}
void MD5Transform(unsigned int state[4],unsigned char block[64])
{
     unsigned int a = state[0];
     unsigned int b = state[1];
     unsigned int c = state[2];
     unsigned int d = state[3];
     unsigned int x[64];
     MD5Decode(x,block,64);
     FF(a, b, c, d, x[ 0], 7, 0xd76aa478); /* 1 */
 FF(d, a, b, c, x[ 1], 12, 0xe8c7b756); /* 2 */
 FF(c, d, a, b, x[ 2], 17, 0x242070db); /* 3 */
 FF(b, c, d, a, x[ 3], 22, 0xc1bdceee); /* 4 */
 FF(a, b, c, d, x[ 4], 7, 0xf57c0faf); /* 5 */
 FF(d, a, b, c, x[ 5], 12, 0x4787c62a); /* 6 */
 FF(c, d, a, b, x[ 6], 17, 0xa8304613); /* 7 */
 FF(b, c, d, a, x[ 7], 22, 0xfd469501); /* 8 */
 FF(a, b, c, d, x[ 8], 7, 0x698098d8); /* 9 */
 FF(d, a, b, c, x[ 9], 12, 0x8b44f7af); /* 10 */
 FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */
 FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */
 FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */
 FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */
 FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */
 FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */
 
 /* Round 2 */
 GG(a, b, c, d, x[ 1], 5, 0xf61e2562); /* 17 */
 GG(d, a, b, c, x[ 6], 9, 0xc040b340); /* 18 */
 GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */
 GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa); /* 20 */
 GG(a, b, c, d, x[ 5], 5, 0xd62f105d); /* 21 */
 GG(d, a, b, c, x[10], 9,  0x2441453); /* 22 */
 GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */
 GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8); /* 24 */
 GG(a, b, c, d, x[ 9], 5, 0x21e1cde6); /* 25 */
 GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */
 GG(c, d, a, b, x[ 3], 14, 0xf4d50d87); /* 27 */
 GG(b, c, d, a, x[ 8], 20, 0x455a14ed); /* 28 */
 GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */
 GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8); /* 30 */
 GG(c, d, a, b, x[ 7], 14, 0x676f02d9); /* 31 */
 GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */
 
 /* Round 3 */
 HH(a, b, c, d, x[ 5], 4, 0xfffa3942); /* 33 */
 HH(d, a, b, c, x[ 8], 11, 0x8771f681); /* 34 */
 HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */
 HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */
 HH(a, b, c, d, x[ 1], 4, 0xa4beea44); /* 37 */
 HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9); /* 38 */
 HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60); /* 39 */
 HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */
 HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */
 HH(d, a, b, c, x[ 0], 11, 0xeaa127fa); /* 42 */
 HH(c, d, a, b, x[ 3], 16, 0xd4ef3085); /* 43 */
 HH(b, c, d, a, x[ 6], 23,  0x4881d05); /* 44 */
 HH(a, b, c, d, x[ 9], 4, 0xd9d4d039); /* 45 */
 HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */
 HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */
 HH(b, c, d, a, x[ 2], 23, 0xc4ac5665); /* 48 */
 
 /* Round 4 */
 II(a, b, c, d, x[ 0], 6, 0xf4292244); /* 49 */
 II(d, a, b, c, x[ 7], 10, 0x432aff97); /* 50 */
 II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */
 II(b, c, d, a, x[ 5], 21, 0xfc93a039); /* 52 */
 II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */
 II(d, a, b, c, x[ 3], 10, 0x8f0ccc92); /* 54 */
 II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */
 II(b, c, d, a, x[ 1], 21, 0x85845dd1); /* 56 */
 II(a, b, c, d, x[ 8], 6, 0x6fa87e4f); /* 57 */
 II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */
 II(c, d, a, b, x[ 6], 15, 0xa3014314); /* 59 */
 II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */
 II(a, b, c, d, x[ 4], 6, 0xf7537e82); /* 61 */
 II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */
 II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb); /* 63 */
 II(b, c, d, a, x[ 9], 21, 0xeb86d391); /* 64 */
     state[0] += a;
     state[1] += b;
     state[2] += c;
     state[3] += d;
}

main.cpp:

#include <afx.h>
#include <iostream>
#include <vector>
#include <cstring>
#include "md5.h"
using namespace std;

struct node{
    unsigned char *s;
    CString fp;
}tmp;

vector<node> cf;

int main(){
    MD5_CTX md5;

    CFileFind finder;
    CFile cfile;
    CFileStatus rStatus;
    BOOL bWorking=finder.FindFile(_T("*.txt"));

    cout<<"正在搜索当前目录下冗余文件..."<<endl;
    while (bWorking){
        bWorking = finder.FindNextFile();
        tmp.fp = (LPCTSTR)finder.GetFilePath();
        CFile::GetStatus(tmp.fp,rStatus);

        CFile file(rStatus.m_szFullName,CFile::modeRead);
        char *FileConten = new char[rStatus.m_size];
        file.Read(FileConten,rStatus.m_size);

        MD5Init(&md5);
        MD5Update(&md5,(unsigned char*)FileConten,rStatus.m_size);
        tmp.s=new unsigned char[16];
        MD5Final(&md5,tmp.s);
        cf.push_back(tmp);

        file.Close();
    }
    for(int i=0;i < cf.size(); i++){
        for(int j=i+1;j < cf.size(); j++){
            if(strcmp((const char*)cf[i].s,(const char*)cf[j].s)){
                cout<<"找到一组冗余文件，正在删除其中冗余文件! "<<endl;
                CFile file(cf[j].fp,CFile::modeRead);
                file.Close();
                file.Remove(cf[j].fp);
                delete cf[j].s;
                cf.erase(cf.begin()+j);
                j--;
            }
        }
    }
    cout<<"已完成操作！"<<endl;
    return 0;
}