sscanf功能详解(转)

在处理字符串的程序当中，经常会分析字符串，从一大长串的字符串截取我们需要的数据，这如果通过自己手写函数来分析，虽然可以，但当你知道sscanf的功能，那就自己写函数分析就显得多此一举。

这些函数的使用都很简单，总结一下，等下次使用一目了然。俗话说：好记性不如烂笔头，记录下来就是效率。

 /*****************************************************
 ** Name         : sscanf.c
 ** Author       : gzshun
 ** Version      : 1.0
 ** Date         : 2011-12
 ** Description  : sscanf function
 ******************************************************/
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 static void sscanf_test(void);

 static void sscanf_test(void)
 {
     int ret;
     char *string;
     int  digit;
     char buf1[];
     char buf2[];
     char buf3[];
     char buf4[];

     /*1.最简单的用法*/
     string = "china beijing 123";
     ret = sscanf(string, "%s %s %d", buf1, buf2, &digit);
     printf("1.string=%s\n", string);
     printf("1.ret=%d, buf1=%s, buf2=%s, digit=%d\n\n", ret, buf1, buf2, digit);
     /*
     **执行结果:
     **1.ret=3, buf1=china, buf2=beijing, digit=123
     **可以看出,sscanf的返回值是读取的参数个数
     */

     /*2.取指定长度的字符串*/
     string = "";
     sscanf(string, "%5s", buf1);
     printf("2.string=%s\n", string);
     printf("2.buf1=%s\n\n", buf1);
     /*
     **执行结果:
     **2.buf1=12345
     */

     /*3.取到指定字符为止的字符串*/
     string = "123/456";
     sscanf(string, "%[^/]", buf1);
     printf("3.string=%s\n", string);
     printf("3.buf1=%s\n\n", buf1);
     /*
     **执行结果:
     **3.buf1=123
     */

     /*4.取到指定字符集为止的字符串*/
     string = "123abcABC";
     sscanf(string, "%[^A-Z]", buf1);
     printf("4.string=%s\n", string);
     printf("4.buf1=%s\n\n", buf1);
     /*
     **执行结果:
     **4.buf1=123abc
     */

     /*5.取仅包含指定字符集的字符串*/
     string = "0123abcABC";
     sscanf(string, "%[0-9]%[a-z]%[A-Z]", buf1, buf2, buf3);
     printf("5.string=%s\n", string);
     printf("5.buf1=%s, buf2=%s, buf3=%s\n\n", buf1, buf2, buf3);
     /*
     **执行结果:
     **5.buf1=123, buf2=abc, buf3=ABC
     */

     /*6.获取指定字符中间的字符串*/
     string = "ios<android>wp7";
     sscanf(string, "%*[^<]<%[^>]", buf1);
     printf("6.string=%s\n", string);
     printf("6.buf1=%s\n\n", buf1);
     /*
     **执行结果:
     **6.buf1=android
     */

     /*7.指定要跳过的字符串*/
     string = "iosVSandroid";
     sscanf(string, "%[a-z]VS%[a-z]", buf1, buf2);
     printf("7.string=%s\n", string);
     printf("7.buf1=%s, buf2=%s\n\n", buf1, buf2);
     /*
     **执行结果:
     **7.buf1=ios, buf2=android
     */

     /*8.分割以某字符隔开的字符串*/
     string = "android-iphone-wp7";
     /*
     **字符串取道'-'为止,后面还需要跟着分隔符'-',
     **起到过滤作用,有点类似于第7点
     */
     sscanf(string, "%[^-]-%[^-]-%[^-]", buf1, buf2, buf3);
     printf("8.string=%s\n", string);
     printf("8.buf1=%s, buf2=%s, buf3=%s\n\n", buf1, buf2, buf3);
     /*
     **执行结果:
     **8.buf1=android, buf2=iphone, buf3=wp7
     */

     /*9.提取邮箱地址*/
     string = "Email:beijing@sina.com.cn";
     sscanf(string, "%[^:]:%[^@]@%[^.].%s", buf1, buf2, buf3, buf4);
     printf("9.string=%s\n", string);
     printf("9.buf1=%s, buf2=%s, buf3=%s, buf4=%s\n\n", buf1, buf2, buf3, buf4);
     /*
     **执行结果:
     **9.buf1=Email, buf2=beijing, buf3=sina, buf4=com.cn
     */

     /*10.过滤掉不想截取或不需要的字符串--补充,
     **在%号后面加一*号,代表过滤这个字符串,不读取
     */
     string = "android iphone wp7";
     sscanf(string, "%s %*s %s", buf1, buf2);
     printf("10.string=%s\n", string);
     printf("10.buf1=%s, buf2=%s\n\n", buf1, buf2);
     /*
     **执行结果:
     **10.android wp7
     */
 }

 int main(int argc, char **argv)
 {
     sscanf_test();

     return ;
 }

 /*
 **测试程序
 **环境:
 **Linux ubuntu 2.6.32-24-generic-pae #39-Ubuntu SMP Wed Jul 28 07:39:26 UTC 2010 i686 GNU/Linux
 **gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
 **
 gzshun@ubuntu:~/c/sscanf$ gcc sscanf.c -o sscanf
 gzshun@ubuntu:~/c/sscanf$ ./sscanf
 1.string=china beijing 123
 1.ret=3, buf1=china, buf2=beijing, digit=123
 2.string=123456789
 2.buf1=12345
 3.string=123/456
 3.buf1=123
 4.string=123abcABC
 4.buf1=123abc
 5.string=0123abcABC
 5.buf1=0123, buf2=abc, buf3=ABC
 6.string=ios<android>wp7
 6.buf1=android
 7.string=iosVSandroid
 7.buf1=ios, buf2=android
 8.string=android-iphone-wp7
 8.buf1=android, buf2=iphone, buf3=wp7
 9.string=Email:beijing@sina.com.cn
 9.buf1=Email, buf2=beijing, buf3=sina, buf4=com.cn
 10.string=android iphone wp7
 10.buf1=android, buf2=wp7
 */