C语言字符串解析

转载

MC6880000057HKD 2021-08-26 11:53:06

文章标签 android 字符串 ios iphone ubuntu 文章分类 代码人生

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。

以下源代码是本人测试的源文件，附带讲解注释。

/***************************************************** 
** 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[255];  
    char buf2[255];  
    char buf3[255];  
    char buf4[255];  
  
    /*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 = "123456789";  
    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 0;  
}  
  
/* 
**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 
*/

/*****************************************************
** 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[255];
	char buf2[255];
	char buf3[255];
	char buf4[255];

	/*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 = "123456789";
	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 0;
}

/*
**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
*/