sscanf()：可以将一个长的字符串按照需求分割成想要的格式

实例：

#include<stdio.h>
#include<string.h>
int main()
{
    //1. 取指定长度的字符串
    char str[100];
    sscanf("12345","%4s",str);
    printf("%s\n",str);//1234

    //2. 格式化时间
    int year, month, day, hour, minute, second;
    sscanf("2013/02/13 14:55:34","%d/%d/%d %d:%d:%d",&year, &month, &day, &hour, &minute, &second);
    printf("time=%d-%d-%d %d:%d:%d\n", year, month, day, hour, minute, second);//time=2013-2-13 14:55:34
    
    //3. %*d和%*s加了（*）表示跳过此数据不读入（也就是不把此数据读入参数中）
    sscanf("1234abcd","%*d%s",str);//此处表示跳过 %d 的数据，也就是跳过 ：1234
    printf("%s\n",str);// abcd
    
    //4. 取到指定字符为止的字符串。如例子所示，遇到‘+’为止的字符串
    sscanf("1234+abc","%[^+]",str);
    printf("%s\n",str);// 1234
    
    //5.  取到指定字符集为止的字符串。如遇到小写字母为止的字符串。
    sscanf("1234+abc1234","%[^a-z]",str);
    printf("%s\n",str);// 1234+
    
    //6. 取仅包含指定字符集的字符串。（取仅包含数字和小写字母的字符串，是取得连续的字符串）。
    sscanf("123456abcdefBFRGTY7890","%[1-9a-z]",str);
    printf("%s\n",str);// 123456abcdef
    
    return 0;
}

实际应用：

读取 pclist_info 文件内容 ，90:2b:34:67:2b:43 [192.168.10.111] [] [] [0 1900/01/00 00:00:00] [Wire] [STATIC] [Online] [] [] [Used]

此函数遇到一个问题，当遇到， [] 第一个符号时，里面是空的，后面的就无法获取了

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



typedef struct {
    char hostClass[8];
    char hostMAC[20];
    char hostDHCPName[70];
    char hostDevName[70];
    char hostIP[20];
    char hostConnectInterface[8];
    char hostOnlineTime[64];
    char hostStotageAccessStatus[8];
}CMCCLanHostInfo;

    int main(void)
    {
        FILE *fp = NULL;
        char line[512] = {0};
        int i=0;
        struct tm timeinfo={0};
        CMCCLanHostInfo tmp_lhi={0};
        char if_mac[20]={0};
        char contype[20]={0};
        char conssid[20]={0};
        char ip_addressing[20]={0};
        char time[128] ="";
        char *p = NULL;
        char dest[] = "[]";
        if ((fp = fopen("pclist_info", "r")) == NULL) {
            printf("%s", "Cannot open pclist_info file!\n");
            return 0;
        }
        if(fgets(line, sizeof(line)-1 , fp) != NULL )
        {
            line[strlen(line)-1] = ‘\0‘;
            
// 90:2b:34:67:2b:43 [192.168.10.111] [0] [1] [0 1900/01/00 00:00:00] [Wire] [STATIC] [Online] 
            sscanf(line, "%[^]%*[^[][%[^]] %*[^[][%[^]] %*[^[][%[^]] %*[^[][%[^]] %*[^[][%[^]] %*[^[][%[^]] %*[^[][%[^]] %*[^[][%[^]] %*[^[][%[^]] %*[^[][%[^]]",
                        tmp_lhi.hostMAC,
                        tmp_lhi.hostIP,
                        tmp_lhi.hostDevName,
                        tmp_lhi.hostDHCPName,
                        time,
                        contype,
                        ip_addressing,
                        tmp_lhi.hostClass,
                        tmp_lhi.hostConnectInterface,
                        conssid,
                        tmp_lhi.hostStotageAccessStatus);
            printf("hostMAC = %s \n",tmp_lhi.hostMAC);
            printf("hostIP = %s \n",tmp_lhi.hostIP);
            printf("hostDevName = %s \n",tmp_lhi.hostDevName);
            printf("hostDHCPName = %s \n",tmp_lhi.hostDHCPName);
            printf("time = %s \n",time);
            printf("contype = %s \n",contype);
            printf("ip_addressing = %s \n",ip_addressing);
            printf("hostClass = %s \n",tmp_lhi.hostClass);
            printf("hostConnectInterface = %s \n",tmp_lhi.hostConnectInterface);
            printf("conssid = %s \n",conssid);
            printf("hostStotageAccessStatus = %s \n",tmp_lhi.hostStotageAccessStatus);

        }
        
        fclose(fp);
        return 0;
    }