mstar面试题 文件目录中有升级包SOFT001.bin，SOFT002.bin，002比001的版本要新，如何写程序识别出最新的升级包。

面试题文件目录中有升级包SOFT001.bin，SOFT002.bin，002比001的版本要新，如何写程序识别出最新的升级包。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>

#define SOFT_STR "SOFT"
int get_version_num_by_filename(const char *filename,int *pnVerNum)
{
int nVerNum = 0;
char *pchBin = NULL;
char *pchS = NULL;
if(NULL == filename ||
0 == strlen(filename))
{
return -1;
}

if(strncmp(filename,SOFT_STR,strlen(SOFT_STR))!= 0)//保证以SOFT_STR开头
{
return -1;
}

pchBin = strstr(filename,".bin");
if(!(NULL != pchBin && 0 == strcmp(pchBin,".bin"))) //保证以.bin末尾
{
return -1;
}

pchS = filename + strlen(SOFT_STR);

while(pchS != pchBin)
{
if(*pchS > '9' || *pchS < '0')
{
return -1;
}

nVerNum = nVerNum*10+(*pchS-'0');
pchS++;
}

*pnVerNum = nVerNum;
return 0;
}

int isDir(int type)
{
if(type == 8) //file
{
return 0;
}
else if(type == 4) //dir
{
return 1;
}
else
{
return -1;
}
}

int GetMaxVersionAndFilename(const char *pathname,char* pchUpgradefilename,int *pnVerNum)
{
struct dirent *pstuDirent = NULL;
DIR *pDirpathTmp = NULL;
int nVerNum = 0;
int nMaxVerNum = -1;
char chUpgradefilename[255] = {0};

if(NULL == pathname ||
0 == strlen(pathname) ||
NULL == pchUpgradefilename ||
NULL == pnVerNum)
{
return -1;
}

pDirpathTmp = opendir(pathname);
if(pDirpathTmp == NULL)
{
printf("\n if(pDirpathTmp == NULL) \n");
return -1;
}

while(NULL != (pstuDirent = readdir(pDirpathTmp)))
{
printf("\n pstuDirent  d_name[%s] d_ino[%lu] d_off[%ld] d_reclen[%d]  d_type[%d]\n",
pstuDirent->d_name,
pstuDirent->d_ino,
pstuDirent->d_off,
pstuDirent->d_reclen,
pstuDirent->d_type
);

if(isDir(pstuDirent->d_type) == 0 && get_version_num_by_filename(pstuDirent->d_name,&nVerNum) == 0)
{
if(nVerNum > nMaxVerNum)
{
memset(chUpgradefilename,0,sizeof(chUpgradefilename));
strncpy(chUpgradefilename,pstuDirent->d_name,sizeof(chUpgradefilename)-1);
nMaxVerNum = nVerNum;
}
}
}

closedir(pDirpathTmp);

printf("\n----------------------------\n");

printf("\nchUpgradefilename[%s] nMaxVerNum[%d]\n",chUpgradefilename,nMaxVerNum);

strncpy(pchUpgradefilename,chUpgradefilename,strlen(chUpgradefilename)+1);
*pnVerNum = nMaxVerNum;

return 0;

}

int main()
{
//getcwd
int nMaxVerNum = -1;
char chUpgradefilename[255] = {0};
GetMaxVersionAndFilename("/share",chUpgradefilename,&nMaxVerNum);
return 0;
}

运行结果

./a.out

 

 pstuDirent  d_name[zlib-1.2.8.tar.gz] d_ino[413168] d_off[187304008] d_reclen[32]  d_type[8]

 

 pstuDirent  d_name[test.out] d_ino[417292] d_off[268019727] d_reclen[20]  d_type[8]

 

 pstuDirent  d_name[a.out] d_ino[391811] d_off[328475253] d_reclen[20]  d_type[8]

 

 pstuDirent  d_name[test.c] d_ino[417290] d_off[367818067] d_reclen[20]  d_type[8]

 

 pstuDirent  d_name[New0001.c] d_ino[413065] d_off[387363692] d_reclen[24]  d_type[8]

 

 pstuDirent  d_name[curl-7.51.0] d_ino[413488] d_off[424798140] d_reclen[24]  d_type[4]

 

 pstuDirent  d_name[SOFT112.bin] d_ino[413074] d_off[509853290] d_reclen[24]  d_type[8]

 

 pstuDirent  d_name[1SOFT111.bin] d_ino[413071] d_off[530715160] d_reclen[24]  d_type[8]

 

 pstuDirent  d_name[SOFT111.txt.bin] d_ino[413072] d_off[622456054] d_reclen[28]  d_type[8]

 

 pstuDirent  d_name[SOFT002.bin] d_ino[413070] d_off[708605345] d_reclen[24]  d_type[8]

 

 pstuDirent  d_name[csdn.c] d_ino[391805] d_off[813129366] d_reclen[20]  d_type[8]

 

 pstuDirent  d_name[1.txt] d_ino[413063] d_off[921009042] d_reclen[20]  d_type[8]

 

 pstuDirent  d_name[curl-7.51.0.tar.gz] d_ino[413166] d_off[971975287] d_reclen[32]  d_type[8]

 

 pstuDirent  d_name[2.txt] d_ino[413064] d_off[982198225] d_reclen[20]  d_type[8]

 

 pstuDirent  d_name[opendir.c] d_ino[413067] d_off[983528440] d_reclen[24]  d_type[8]

 

 pstuDirent  d_name[zlib-1.2.8] d_ino[413169] d_off[1002493285] d_reclen[24]  d_type[4]

 

 pstuDirent  d_name[123.rmvb] d_ino[417304] d_off[1011954566] d_reclen[20]  d_type[8]

 

 pstuDirent  d_name[ffmpeg_learn] d_ino[417309] d_off[1273990568] d_reclen[24]  d_type[4]

 

 pstuDirent  d_name[ProFFmpeg] d_ino[417293] d_off[1310706302] d_reclen[24]  d_type[4]

 

 pstuDirent  d_name[ffmpeg-3.1.6] d_ino[392753] d_off[1345889369] d_reclen[24]  d_type[4]

 

 pstuDirent  d_name[yasm-1.3.0] d_ino[407880] d_off[1381087985] d_reclen[24]  d_type[4]

 

 pstuDirent  d_name[.] d_ino[391804] d_off[1451847256] d_reclen[16]  d_type[4]

 

 pstuDirent  d_name[..] d_ino[2] d_off[1486652463] d_reclen[16]  d_type[4]

 

 pstuDirent  d_name[ffmpeg-3.1.6.tar.gz] d_ino[392754] d_off[1594763545] d_reclen[32]  d_type[8]

 

 pstuDirent  d_name[SOFT666660.bin] d_ino[413075] d_off[1671722948] d_reclen[28]  d_type[8]

 

 pstuDirent  d_name[SOFT233.bin] d_ino[413068] d_off[1725054639] d_reclen[24]  d_type[4]

 

 pstuDirent  d_name[SOFT1.txt] d_ino[413073] d_off[1749282150] d_reclen[24]  d_type[8]

 

 pstuDirent  d_name[New0002.c] d_ino[413066] d_off[1768036029] d_reclen[24]  d_type[8]

 

 pstuDirent  d_name[simple.out] d_ino[417306] d_off[1865870150] d_reclen[24]  d_type[8]

 

 pstuDirent  d_name[learn] d_ino[413054] d_off[1921161435] d_reclen[20]  d_type[4]

 

 pstuDirent  d_name[sdasdSOFT1asd.bin] d_ino[413069] d_off[1936555055] d_reclen[32]  d_type[4]

 

 pstuDirent  d_name[simple_ffmpeg_player.c] d_ino[417303] d_off[2080791565] d_reclen[36]  d_type[8]

 

 pstuDirent  d_name[yasm-1.3.0.tar.gz] d_ino[407879] d_off[2080931987] d_reclen[32]  d_type[8]

 

 pstuDirent  d_name[output.yuv] d_ino[417308] d_off[2138376756] d_reclen[24]  d_type[8]

 

 pstuDirent  d_name[mySDLFirst.out] d_ino[417291] d_off[2147483647] d_reclen[28]  d_type[8]

 

----------------------------

 

chUpgradefilename[SOFT666660.bin] nMaxVerNum[666660]

root@ubuntu:/share#