C를 사용하여 시간을 밀리 초 단위로 표시하는 방법

Question

정렬 한 후 두 파일을 결합하고 평균 시간을 얻는 데 필요한 타이밍을 평가합니다. 하지만 코딩에 따르면 초 단위로 표시되기 때문에 실행이 1 초 만에 결과를 얻을 정도로 빠르기 때문에 평균값을 얻는 데는 아무 것도 없습니다. 그래서 시간을 밀리 초 단위로 출력하여 평균치를 계산할 수 있습니다. 여기 내 코드가 있습니다 -

#include <sys/stat.h> // S_IRUSR 
#include <time.h>  // time_t time 
#include "mergesort.h" 

typedef struct { 
int fd; //file description ID 
int type; //the schema type of file 
page_t *page; //page buffer which use to store records 
} file_t; 


/*! \fn file_t *file_init(char *file_path, int type, int page_size) 
* \brief initialize the file structure with inputted parameters 
* \param file_path the path of need to handled file  
* \param type the type of file. 
*   1 means the file formated with characters schema 
*   2 means the file formated with guilds schema 
* \param page_size the size of page, the page will use to buffer the 
*   record which read from file 
* \return not NULL the file structure 
*   NULL means cannot construct the file structure 
*/ 
file_t *file_init(char *file_path, int type, page_t *page) 
{ 
file_t *file = calloc(1, sizeof(file_t)); 

char sorted_file[1024] = {0}; 
snprintf(sorted_file, 1023, "%s.sorted", file_path); 
file->fd = open(sorted_file, S_IRUSR); 
file->type = type; 
file->page = page; 
return file; 
} 

int merge_sort(pass_t *pass, int page_size, int page_num, char *file) 
{ 
int ret = OK; 
if (pass->pages == NULL) 
{ 
    pass->pages = calloc(pass->page_num, sizeof(page_t)); 
} 

// parse input 
pass->page_size = page_size; 
pass->page_num = page_num; 
pass->input_file = file; 
pass->output_file = "/tmp/merge_tmp"; 
pass->type = 1; 
if (strstr(pass->input_file, "guilds") != NULL) 
{ 
    pass->type = 2; 
} 


// pass 0: split the original into sorted file pieces 
pass_0(pass); 

// pass n: merge the file pieces into a sorted unique file 
return pass_n(pass); 
} 

/*! \fn int main(int argc, char *argv[]) 
* \brief the entry of program 
* \param argc the number of input parameters 
* \param argv the list of input parameters 
*   1st is program name 
*   2nd is the optional flag to indicate ouput matched record to screen 
*   2nd or 3rd is the record size of page 
*   3rd or 4th is the page size 
*   4th or 5th is one file which need to be merged 
*   5th or 6th is another file which need to be merged 
* \return 0 indicate the operation is success 
*   other indicate the operation is failed 
*/ 
int main(int argc, char *argv[]) 
{ 
if (argc < 4) 
{ 
    fprintf(stderr, 
      "Usage: bin/sortmerge [-o] <pagesize> <buffers> <path>\n"); 
    exit(1); 
} 

int param_id = 1; 
int out_flag = 0; 
if (strcmp(argv[param_id], "-o") == 0) 
{ 
    out_flag = 1; 
    param_id++; 
} 

int page_size = atoi(argv[param_id++]); 
int page_num = atoi(argv[param_id++]); 
int total_buf = page_size * page_num; 

int ret = OK; 
int tuples_num = 0; 
time_t start = time(NULL); 

pass_t file1_pass = {0}; 
merge_sort(&file1_pass, page_size, page_num, argv[param_id++]); 

pass_t file2_pass = {0}; 
// reuse the allocated buffer 
file2_pass.pages = file1_pass.pages; 
merge_sort(&file2_pass, page_size, page_num, argv[param_id++]); 

// open sorted file 
file_t *chars_file = NULL; 
file_t *guilds_file = NULL; 
if (strstr(file1_pass.input_file, "guilds") != NULL) 
{ 
    chars_file = file_init(file2_pass.input_file, 1, &file2_pass.pages[0]); 
    guilds_file = file_init(file1_pass.input_file, 2, &file1_pass.pages[1]); 
} 
else 
{ 
    chars_file = file_init(file1_pass.input_file, 1, &file1_pass.pages[0]); 
    guilds_file = file_init(file2_pass.input_file, 2, &file2_pass.pages[1]); 
} 

record_t *guild_record = NULL; 
record_t *char_record = NULL; 
PAGE_BEFORE(chars_file->page, page_size); 
PAGE_BEFORE(guilds_file->page, page_size); 
do 
{ 
    // load and popup record from guilds 
    page_load(guilds_file->fd, guilds_file->page, guilds_file->type, 
      guilds_file->type); 
    guild_record = page_pop_record(guilds_file->page); 
    if (guild_record == NULL) 
    { 
     //no record then exit 
     break; 
    } 

    do 
    { 
     // load popup record from characters 
     page_load(chars_file->fd, chars_file->page, chars_file->type, 
       chars_file->type); 
     char_record = page_pop_record(chars_file->page); 
     if (char_record != NULL 
       && guild_record->guild_id == char_record->guild_id) 
     { 
      // records matched with guild_id 
      tuples_num++; 
      if (out_flag == 1) 
      { 
       // output matched record information 
       printf("%d,%s,%d,%d,%d,%s\n", char_record->guild_id, 
         char_record->info.character.cname, 
         char_record->info.character.team, 
         char_record->info.character.level, 
         char_record->info.character.cid, 
         guild_record->info.guild.gname); 
      } 
     } 

     // if not find bigger than guild tuple record, 
     // continuously popup record from characters 
    } 
    while (char_record != NULL 
      && guild_record->guild_id >= char_record->guild_id); 

} 
while (guild_record != NULL && char_record != NULL); 

printf("Number of tuples: %d\nTime: %d seconds\n", 
     tuples_num, (time(NULL) - start)); 
return 0; 
} 

Answer 1

time() 대신 clock()을 사용하십시오. clock()으로 시간 (NULL)을 변경할 수 있어야합니다. clock_t는 time_t를 대체 할 수 있습니다.