Question

我想要验证哪些MET数据看起来像这样：

char validBuffer[] = {"N51374114W1160437"};
char invalidBuffer[] = {"bad data\n"};
char emptyBuffer[] = {""};

我尝试过一个简单的sscanf，但失败了：

int _tmain(int argc, _TCHAR* argv[])
{

    char validBuffer[] = {"N51374114W1160437"};
    char invalidBuffer[] = {"bad data\n"};
    char emptyBuffer[] = {""};

    char ns = ' ';
    char ew = ' ';
    int northing = -999;
    int easting = -999;

    int paramsConverted = sscanf_s(validBuffer, "%c%d%c%d", &ns, &northing, &ew, &easting);
    printf("Converted \"%s\"; Found %d params [%c,%d,%c,%d]\n", validBuffer, paramsConverted, ns, northing, ew, easting);

    paramsConverted = sscanf_s(invalidBuffer, "%c%d%c%d", &ns, &northing, &ew, &easting);
    printf("Converted \"%s\"; Found %d params [%c,%d,%c,%d]\n", invalidBuffer, paramsConverted, ns, northing, ew, easting);

    paramsConverted = sscanf_s(validBuffer, "%c%d%c%d", &ns, &northing, &ew, &easting);
    printf("Converted \"%s\"; Found %d params [%c,%d,%c,%d]\n", emptyBuffer, paramsConverted, ns, northing, ew, easting);

    getchar();

    return 0;
}

给了我：

Converted "N51374114W1160437"; Found 2 params [N,-999,",-1024]
Converted "bad data
"; Found 1 params [b,-999,",-1024]
Converted ""; Found 2 params [N,-999,",-1024]

如果可能的话，我宁愿不使用任何外部库，那么有没有一种简单的方法可以一次解析一个字符呢？

Answer 1

如何使用Regular expressions from TR1？

Answer 2

char validBuffer[] = {"N51374114W1160437"};
    char invalidBuffer[] = {"bad data\n"};
    char emptyBuffer[] = {""};

    if(strlen(validBuffer)!=18)
    {
//Error not valid buffer
    }
    char ns = validBuffer[0];
    char ew = validBuffer[9];
    int N = atoi(&validBuffer[1]);
    int W = atoi(&validBuffer[10]);
    if(N==0 || W==0)
        //Error not valid buffer

不是简单不是最好的，但总比没有好

Answer 3

您可以使用std::stringstream和流媒体操作符......

#include <string>
#include <sstream>
#include <iostream>

using namespace std;

bool parse(string & s) {
    stringstream ss(s);
    char n = 0, w = 0;
    int x = 0, y = 0;
    ss >> n;
    if (! ss.good ()) return false;
    ss >> x;
    if (! ss.good ()) return false;
    ss >> w;
    if (! ss.good ()) return false;
    ss >> y;
    if ( ss.bad ()) return false;

    cout << "Parsed {" << n << ", " << x << ", "
         << w << ", " << y << "}" << endl;
    return true;
}

int main ()
{

    string validBuffer = "N51374114W1160437";
    string invalidBuffer = "bad data\n";
    string emptyBuffer = "";

    if (! parse (validBuffer))
        cout << "Unable to parse: '" << validBuffer << "'" << endl;
    if (! parse (invalidBuffer))
        cout << "Unable to parse: '" << invalidBuffer << "'" << endl;
    if (! parse (emptyBuffer))
        cout << "Unable to parse: '" << emptyBuffer << "'" << endl;

    return 0;
}

我的输出使用上面的内容：

Parsed {N, 51374114, W, 1160437}
Unable to parse: 'bad data
'
Unable to parse: ''

Answer 4

考虑sscanf（）的位特定格式参数：

int paramsConverted = sscanf(validBuffer, "%c%8d%c%7d", &ns, &northing, &ew, &easting);

在C ++中验证GPS字符串的最简单方法？

4 个答案: