纯C 实现 strpos substr strspilt str_trim

在C 语言中没有C++ 好用的 spilt 方法 (STL 带的也不怎么好用)

  1 #include <stdio.h>
  2 #include <string.h>
  3 #include <iostream>
  4 using namespace std;
  5 
  6 int Cstrpos(char *haystack, const char *needle)
  7 {
  8     char *p;
  9     p = strstr(haystack, needle);
 10     if(p)
 11     {
 12         return p - haystack;
 13     }
 14     return -1;
 15 }
 16 
 17 int Csubstr(char *haystack, int start, int len, char *out)
 18 {
 19     int i;
 20     for(i=0; i<len; i++)
 21     {
 22         out[i] = haystack[start+i];
 23     }
 24     return 0;
 25 }
 26 
 27 char *Csplit(char *haystack, const char *needle, char *out)
 28 {
 29     int start, end, offset, i;
 30     //match start
 31     if(0 == memcmp(haystack, needle, strlen(needle)))
 32     {
 33         start = Cstrpos(haystack, needle);
 34         if(-1 == start)
 35         {
 36             return NULL;
 37         }
 38     }
 39     else
 40     {
 41         start = 0;    
 42     }
 43     end   = Cstrpos(haystack+start, needle);
 44     if(-1 == end)
 45     {
 46         end = strlen(haystack) - start;
 47     }
 48     offset = end;
 49     
 50     for(i=0; i<offset; i++)
 51     {
 52         out[i] = haystack[i];
 53     }
 54     haystack += i+1; 
 55     
 56     return haystack;
 57 }
 58 
 59 int main(int argc, char **argv)
 60 {
 61     //char *str = "123,456,789"; //2个测试字符串
 62     char *str = "123";
 63     cout<<str<<endl;
 64     
 65     int pos1;
 66     pos1 = Cstrpos(str, ",");
 67     cout<<pos1<<endl;
 68     
 69     char out[10] = {0};
 70     
 71     //Csubstr(str, 1, 3, out);
 72     //cout<<out<<endl;
 73     
 74     cout<<"+++++++++++++++++++++"<<endl;
 75     
 76     memset(out, 0, 10);
 77     str = Csplit(str, ",", out);
 78     cout<<out<<endl;
 79     
 80     cout<<"+++++++++++++++++++++"<<endl;
 81     
 82     memset(out, 0, 10);
 83     str = Csplit(str, ",", out);
 84     cout<<out<<endl;
 85     
 86     
 87     cout<<"+++++++++++++++++++++"<<endl;
 88     
 89     memset(out, 0, 10);
 90     str = Csplit(str, ",", out);
 91     cout<<out<<endl;
 92         
 93     cout<<"+++++++++++++++++++++"<<endl;
 94     
 95     memset(out, 0, 10);
 96     str = Csplit(str, ",", out);
 97     cout<<out<<endl;
 98     
 99     return 0;
100 }

 

因为也包含了测试程序 使用 cout 输出，所以使用 g++ 编译，执行。但3个函数是 可以移值到 ARM 、 KEIL、STM32 中的。

测试123,456,789

测试123

 

这个，目前还有一个缺点，分隔符只支持1个字符。 

补发一个，实现的 str_trim 函数  需要头文件 #include <ctype.h>

 1 static void str_trim(char *str)
 2 {
 3     int len;
 4     char *copy;
 5     char *end, *start;
 6     
 7     len   = strlen(str);
 8     copy  = (char *)malloc(len + 1);
 9     
10     if(! copy)
11     {
12         logd("malloc error \n");
13         return ;
14     }
15     
16     memset(copy, 0, len + 1);
17     strcpy(copy, str);
18     start = copy;
19     end   = start + len - 1;
20     
21     while(end >= start)
22     {
23         if(! isgraph(*end))
24         {
25             *end = '\0';
26             end--;
27         }
28         else
29         {
30             break;
31         }
32     }
33     
34     len   = strlen(copy);
35     end   = start + len - 1;
36     while(start <= end)
37     {
38         if(! isgraph(*start))
39         {
40             start++;
41         }
42         else
43         {
44             break;
45         }
46     }
47 
48     strcpy(str, start);
49     free(copy);
50 }

 

posted @ 2018-03-21 15:17  宁次  阅读(977)  评论(0)  编辑  收藏  举报