程式需求：例如有目錄a和b,需要找出兩者之下同名的檔案，記住是同名不需要格式一樣，然後將同名的檔案從a拷貝到另外一個目錄c下。

實現如下：（實現了將f盤下a目錄和b目錄中同名檔案從a拷貝到c中）

#include<stdlib.h> #include<stdio.h> #include<iostream> #include<dirent.h> #include<vector> #include<iterator> #include<string> #define DIRO "f:/a/" #define DIRT "f:/b/" #define DIRTH "f:/c/" #define SIZEOFBUFFER 256*1024L using namespace std; string ddot(string s){ string str; unsigned int pos=s.find("."); str=s.substr(0,s.size()-pos-2); return str; } long filesize(FILE *stream) { long curpos, length; curpos = ftell(stream); fseek(stream, 0L, SEEK_END); length = ftell(stream); fseek(stream, curpos, SEEK_SET); return length; } int copyfile(const char* src,const char* dest) { FILE *fp1,*fp2; int fsize,factread; static unsigned char buffer[SIZEOFBUFFER]; fp1=fopen(src,"rb"); fp2=fopen(dest,"wb"); if (!fp1 || !fp2) return 0; for (fsize=filesize(fp1);fsize>0;fsize-=SIZEOFBUFFER) { factread=fread(buffer,1,SIZEOFBUFFER,fp1); fwrite(buffer,factread,1,fp2); } fclose(fp1); fclose(fp2); return 1; } int main() { DIR *dir1; DIR *dir2; struct dirent *d1; struct dirent *d2; vector<string> sour1; vector<string> sour2; if((dir1=opendir(DIRO))==NULL){ cout<<"open directory "<<DIRO<<" failed~~!"; } if((dir2=opendir(DIRT))==NULL){ cout<<"Open directory "<<DIRT<< "failed~!"; } while((d1=readdir(dir1))!=NULL){ if(strcmp(d1->d_name,".")!=0 && strcmp(d1->d_name,"..")!=0) sour1.push_back(d1->d_name); } while((d2=readdir(dir2))!=NULL){ if(strcmp(d2->d_name,".")!=0 && strcmp(d2->d_name,"..")!=0) sour2.push_back(d2->d_name); } for(vector<string>::iterator iter1=sour1.begin();iter1!=sour1.end();iter1++) for(vector<string>::iterator iter2=sour2.begin();iter2!=sour2.end();iter2++){ string s1=ddot(*iter1); string s2=ddot(*iter2); if((s1.compare(s2))==0){ s1=DIRO+*iter1; const char * tmp1=s1.c_str(); char * s; strcpy(s,tmp1); string des=DIRTH+*iter1; const char * tmp2=des.c_str(); copyfile(s,tmp2); } } system("pause"); return 0; }

opendir用於開啟目錄，是類似於流的那種方式，返回一個指向DIR結構體的指標他的引數*dirname是一個字元陣列或者字串常量

readdir函式用於讀取目錄，只有一個引數，這個引數主opendir返回的結構體指標，或者叫控制代碼更容易理解些吧。這個函式也返回一個結構體指標 dirent * ，dirent的結構如下定義
                   struct dirent
                   {
                       long d_ino;                      /* inode number */
                       off_t d_off;                     /* offset to this dirent */
                       unsigned short d_reclen;         /* length of this d_name */
                       char d_name [NAME_MAX+1];        /* file name (null-terminated) */
                   }

if(strcmp(d->d_name, ".") != 0 && strcmp(d->d_name, "..") != 0)
如果不加這句，會輸出目錄，輸出結果：
.
..
1.txt
2.txt