通过sscanf处理GPS信息

C语言提供了scanf通过IO格式化输入字符串，同样也提供了sscanf可以处理字符串，用于提取字符串中的有用信息。

之前在处理字符串的时候都是一个个字符遍历，如果要取中间的数值，还得把字符转为数字，然后做乘法加法，很是麻烦。

用sscanf可以将原来几十行的代码简化到一两行，见以下程序。

#include <stdio.h>#include <stdlib.h>#include <string.h>typedefunsigned intUINT32;typedefunsigned long longUINT64;typedefUINT32BOOL;#defineTRUE1#defineFALSE0/* 日期时间结构体 8 bytes */#pragma pack(1) typedef union _ZGDateTime{UINT64 Ticks;struct  _tm{UINT32US: 12;UINT32MS: 12;UINT32Second: 8;UINT32Minute: 6;UINT32Hour: 5;UINT32Day: 5;UINT32Month: 4;UINT32Year: 12;}tm;}ZGDateTime;/* 定义GPS信息结构体 */typedef struct _GPS_INFO_STRU{ZGDateTimedt;charstatus;// 状态A-有效,V为非有效接收警告，即当前天线视野上方的卫星个数少于3颗。floatlatitude_value;// 纬度值charlatitude;// 纬度为N南纬或S北纬float longtitude_value;// 经度值    char longtitude;// 经度标明东西半球，E为东半球、W为西半球float speed;// 速度    float azimuth_angle;// 方位角}GPS_INFO;/*获取GPS信息，只处理$GPRMC*/BOOL GetGpsInfo(const char *pStr, GPS_INFO *pGpsInfo){BOOL bl;int i;int year,month,day,hour,minute,second,ms;ZGDateTime*dt;dt = &pGpsInfo->dt;memset(pGpsInfo, 0, sizeof(GPS_INFO));i = sscanf(pStr, "$GPRMC,%2d%2d%2d.%d\  %*[^VAva]%c,\  %f%*[^SNsn]%c,\  %f%*[^EWew]%c,\  %f,%f,\  %2d%2d%2d",    &hour, &minute, &second, &ms,  &pGpsInfo->status, &pGpsInfo->latitude_value, &pGpsInfo->latitude,  &pGpsInfo->longtitude_value, &pGpsInfo->longtitude,  &pGpsInfo->speed, &pGpsInfo->azimuth_angle,  &day, &month, &year  );if(i >= 14 && (pGpsInfo->status == 'A' || pGpsInfo->status == 'a')){dt->tm.Year = 2000+year;dt->tm.Month = month;dt->tm.Day = day;dt->tm.Hour = hour;dt->tm.Minute = minute;dt->tm.Second = second;dt->tm.MS = ms;dt->tm.US = 0;bl = TRUE;}else{bl = FALSE;}return bl;}int main(){const char TestGpsText[]={"$GPRMC,024813.640,a,3158.4608,N,11848.3737,E,10.05,324.27,150706,,,A*50"};GPS_INFOgpsInfo;GPS_INFO*pGpsInfo;ZGDateTime*dt;BOOLbl;pGpsInfo = &gpsInfo;dt = &pGpsInfo->dt;bl = GetGpsInfo(TestGpsText, pGpsInfo);if(bl == TRUE){printf( "%s %s\r\n", __DATE__, __TIME__);printf( "GPS信息：\r\n");printf( "时  间：%04d-%02d-%02d %02d:%02d:%02d %03d.%03d\r\n",   dt->tm.Year, dt->tm.Month, dt->tm.Day,   dt->tm.Hour, dt->tm.Minute, dt->tm.Second,   dt->tm.MS, dt->tm.US);printf( "状  态：%s\r\n", pGpsInfo->status == 'A' ? "有效" : "无效");printf( "经  度：%s%0.4f度\r\n", pGpsInfo->longtitude == 'E'? "东经" : "西经", pGpsInfo->longtitude_value);printf( "纬  度：%s%0.4f度\r\n", pGpsInfo->latitude == 'N'? "北纬" : "南纬", pGpsInfo->latitude_value);printf( "速  度：%.3f\r\n", pGpsInfo->speed);printf( "方位角：%.3f\r\n\r\n", pGpsInfo->azimuth_angle);}else{printf( "GPS数据无效\r\n");}system("pause");}