file search in c++

Question

I just started learning c++ and am currently using codeblocks. i wanna write an application that can search for files in directory including it's subdirs, but i cant seem to find any good examples for this and i've read somewhere that this is only possible through a library like boost.

1. is this true?
2. any examples for doing it without library?

thanks in advance

Answer 1

It's also possible to use it using OS system calls, readdir on linux for example. boost (and other libraries) will allow you to write portable code for several (all?) OSes.

Here u can find elaborate examples http://faq.cprogramming.com/cgi-bin/smartfaq.cgi?answer=1046380353&id=1044780608

Answer 2

Yes, it's true: standard C++ does not have APIs for listing the content of a directory.

So you either do it through a library (Boost or others) or through the native calls for the operating system you're using (FindFirstFile/FindNextFile on Windows, opendir/readdir on Unix). Others answers have example code.

But if you just started learning C++ it is probably better to not struggle with these for now. Focus on learning standard C++ for the beginning. Writing the application you had in mind is an useful exercise but I would postpone it a little until after you are more familiar with standard C++.

Answer 3

Boost isn't the only way of scanning directories but it's probably the easiest way to do it in a platform-neutral way - i.e. without using a platform-specific API (such as Win32).

Here's a simple example using boost:

#include <boost/filesystem.hpp>
#include <iostream>
#include <iterator>
#include <set>

std::set<boost::filesystem::path> getDirContents (const std::string& dirName)
{
    std::set<boost::filesystem::path> paths;
    std::copy
        ( boost::filesystem::directory_iterator (dirName)
        , boost::filesystem::directory_iterator ()
        , std::inserter (paths, paths.end ())
        );

    return paths;
}

int main (int argc, char* argv[])
{
    std::set<boost::filesystem::path> paths = getDirContents ("C:\\");
    std::copy
        ( paths.begin ()
        , paths.end ()
        , std::ostream_iterator<boost::filesystem::path> (std::cout, "\n")
        );
    return 0;
}

Answer 4

This script is used to collect files creation and modification date information from your system drive, we can search any date to know the results and all output will be stored in a flat file, so its easier to view the log. Before running this program, please confirm the read/write permission for the output flat file (FileList.txt).

It helps to know what all files are created/update on those given search date. Most malware programs try to inject/affect the files, so it helps to debug those affected files. I wrote this script using Borland C++ 5.5 Version under Windows Platform.

Please find the source code from my tech blog - http://www.algonuts.info/how-to-trace-file-creation-and-modification-date-using-c-programming.html

#include<iostream.h>
#include<conio.h>
#include<dirent.h>
#include<dir.h>
#include<process.h>
#include<string.h>
#include<stdio.h>
#include<io.h>
#include<dos.h>
#include<sys/stat.h>

int found=0;
struct ffblk vfile;
unsigned long int udata;
char ch,present[MAXPATH];
int year,month,day;

int next_directory(char *);
void scan_directory(char *);

void main(int account,char *arg[],char *env[])
{   
    clrscr();
    getcwd(present,MAXPATH);

    DIR *dir; 
    struct dirent *temp;
    cout<<"\nWelcome to Finder for file view";
    cout<<"\n\nEnter drive:";
    cin>>ch;

    char base[]="X:\\";
    base[0]=ch;
    if ((dir = opendir(base)) == NULL)
    { 
        clrscr();
        cout<<"\nError : Derive not found";  
        getch(); 
        exit(0); 
    }
    else
    {
        if(access("FileList.txt",0)==0)
        unlink("FileList.txt");
        cout<<"\n\n\nScan Date Details:";
        cout<<"\n\nEnter Year:";
        cin>>year;
        cout<<"\nEnter Month:";
        cin>>month;
        if( !(month>=1 && month<=12) )
        {
            clrscr();
            cout<<"\nError:Value of month is not exist";
            getch();
            exit(0);                
        }
        cout<<"\nEnter Day:";
        cin>>day;
        if( !(day>=1 && day<=31) )
        {
            clrscr();
            cout<<"\nError:Value of day is not exist";
            getch();
            exit(0);                
        }
    }

    scan_directory(base);
    while ((temp = readdir(dir)) != NULL)
    {
        char  *directory = (char *) malloc(3+strlen(temp->d_name)+1);
        strcpy(directory,base);
        strcat(directory,temp->d_name);
        next_directory(directory);
        free(directory);
    }
    closedir(dir);

    clrscr();
    if(access("FileList.txt",0)==0)
    cout<<"\n\nSystem: Successfully Find all files and stored in FileList.txt";
    else
    cout<<"\n\nSystem: No file has Modified on"<<day<<"//"<<month<<"//"<<year;
    sleep(3);   
}

int next_directory(char *path)
{
    int count=0;
    DIR *dirtemp; 
    char *hold,*temp;
    struct dirent *ptemp;


    hold=path;
    if ((dirtemp = opendir(path)) != NULL)
    scan_directory(path);
    else
    return 0;


    while ((ptemp = readdir(dirtemp)) != NULL)
    {     
        char *directory = (char *) malloc(1+strlen(ptemp->d_name)+1);
        directory[0]='\\';
        strcpy(directory+1,ptemp->d_name);
        if(directory[1]!='\.')
        {
            count=strlen(hold);
            temp = (char *) malloc(strlen(hold)+strlen(directory)+1);
            strcpy(temp,hold);
            strcat(temp,directory);
            free(directory);
            if(opendir(temp)!=NULL)
            next_directory(temp); 
            temp[count]='\0'; 
            free(temp+count+1);
            hold=temp;
        }
        else
        free(directory);
    }
    closedir(dirtemp);
    return 0;
}

void scan_directory(char *tempo)
{
    cout<<"\n"<<tempo;

    FILE *stream;
    struct ftime ft;

    if(present[0]==tempo[0])
    chdir(tempo);  
    else
    {
        setdisk(tempo[0]-65);
        chdir(tempo); 
    }

    udata = findfirst("*.*",&vfile,0x02);
    while (!udata)
    {  
        stream = fopen(vfile.ff_name,"r");
        if(stream==NULL)
        {
            fclose(stream);
            udata=findnext(&vfile);
            continue;
        }
        else
        {
            getftime(fileno(stream), &ft);
            if(year==ft.ft_year+1980 && month==ft.ft_month && day==ft.ft_day)
            {
                //cout<<"\n"<<tempo<<" "<<vfile.ff_name<<"  Hour:"<<ft.ft_hour<<"  Min:"<<ft.ft_min<<"  Sec:"<<ft.ft_tsec *2;
                if(present[0]==tempo[0])    
                system("cd\\");
                chdir(present); 

                char string[25];
                FILE *fp = fopen("FileList.txt","a+");

                if(found==0)
                {
                    fputs("Scan Date: ",fp);
                    itoa(ft.ft_day, string, 10);
                    fputs(string,fp);
                    fputc('\\',fp);

                    itoa(ft.ft_month, string, 10);
                    fputs(string,fp);
                    fputc('\\',fp);

                    itoa((ft.ft_year+1980), string, 10);
                    fputs(string,fp);
                    fputs("\n\n",fp);
                    found=1;
                }

                unsigned get;
                _dos_getfileattr(vfile.ff_name,&get);
                if (get & _A_HIDDEN)
                fputs("[Hidden File]  ",fp);

                get=0;
                if(ft.ft_hour<10)
                get=1;
                itoa(ft.ft_hour, string, 10);
                fputs(string,fp);
                fputc('\\',fp);

                if(ft.ft_min<10)
                get=get+1;
                itoa(ft.ft_min, string, 10);
                fputs(string,fp);
                fputc('\\',fp);

                if(ft.ft_tsec<10)
                get=get+1;
                itoa(ft.ft_tsec, string, 10);
                fputs(string,fp);

                for(int count=0;count<get;count++)
                fputs(" ",fp);

                fputs("  ",fp);
                fputs(tempo,fp);
                fputs("   ",fp);

                fputs(vfile.ff_name,fp);
                fputc('\n',fp);
                fclose(fp);

                if(present[0]==tempo[0])
                chdir(tempo);  
                else
                {
                    setdisk(tempo[0]-65);
                    chdir(tempo); 
                }
            }
            fclose(stream);
        }
        udata=findnext(&vfile);
    }
    if(present[0]==tempo[0])    
    system("cd\\");
    chdir(present);
}