如何查找表达式的哪个索引与正则表达式匹配

Question

如何修改此代码以便它找到正则表达式匹配的索引。基本上假设我有“金”作为我的测试表达。我的测试字符串是“jkimsdfs”。我怎么能证明“jkimsdfs”在索引与“金”匹配1.

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

int main() { 

     char word[100]; //sets the limit of characters within word to 99(0-99 

     char exp[100]; //sets the limit of characters within exp to 99(0-99) 

     regex_t w; //contains size_t. This field holds the number of 
     //parenthetical subexpressions in the regular expression that was compiled. 

     int status; // integer status 

     printf("Test Expression: "); //print "Test Expression" 

     fgets(word,100,stdin); // 

     word[strlen(word)-1] = '\0'; 
     status = regcomp(&w,word,REG_EXTENDED|REG_NOSUB); 
     printf("%d\n", status); 
     printf("Validity of regex, if 0 than it matches: %d\n",status); 
     if (status) return 1; 
     while (1) { 
      printf("Test String: "); 
      fgets(exp,100,stdin); 
      exp[strlen(exp)-1] = '\0'; 
      if (strlen(exp) < 1) 
      break; 
      status = regexec(&w,exp,(size_t)0,NULL,0); 
      printf("Matched: %d\n",status); 
      printf("%d\n", status); 
      } 
      regfree(&w); 
     return 0; 
     } 

Answer 1

您可以使用strstr：

char str[] = "jkimsdfs"; 
char *ptr; 

if ((ptr = strstr(str, "kim"))) { 
    if ((ptr - str) == 1) { 
     /* Match */ 
    } 
} 

Answer 2

也许文档说得到匹配的位置将是

size_t  nmatch = 2; 
regmatch_t pmatch[2]; 

status = regexec(&w, exp, nmatch, pmatch, 0); 
if (status == 0) 
{ 
    printf("Matched \"%.*s\" at position %d.\n", 
     pmatch[1].rm_eo - pmatch[1].rm_so, &exp[pmatch[1].rm_so], 
     pmatch[1].rm_so); 
} 
else 
    printf("Match not found\n");