Question

我觉得这是一个愚蠢的问题，但我很累，所以我只想问这里。我的矢量大小从2变为0.首先我调用过程：

void PPM::process(pmode_t pmode, const string &fname) 
{
// read qcolors in fname
read_qcolors(fname);

// run proper process mode
if (pmode == run_process1) process1();
else process2();
return;
}

调用read_qcolors（），它创建一个大小为2的向量：

void PPM::read_qcolors(const string &fname)
{
// open fname: check status
// 
// while (more data0 {
//   read R G B values
//   save to qcolors vector
// }
// 
// close input file
ifstream filestream;
vector <RGB> qcolors;
string line;
stringstream ss;
unsigned int ui1, ui2, ui3;

cerr << "reading " << fname << '\n';

filestream.open(fname.c_str());
if (filestream.fail()) cerr << "qcolors file failed to open.\n";
while (getline(filestream, line)) {
        if (filestream.eof()) break;
        if (filestream.fail()) cerr << "error during reading of qcolors file.\n";
        RGB rgb;
        ss.str(line);
        /* Apparently there are no formatting flags to tell
           a stringstream to read a stream as uchars. So I store
           the stream into insigned ints, then convert the unsigned
           ints to unsigned chars when assigning the RGB values. */
        ss >> ui1 >> ui2 >> ui3;
        rgb.R = (unsigned char)ui1;
        rgb.G = (unsigned char)ui2;
        rgb.B = (unsigned char)ui3;
        //empty stringstream
        ss.str("");
        //reset state flags
        ss.clear();
        qcolors.push_back(rgb);
}
filestream.close();
cerr << "qcolor size is " << qcolors.size() << '\n';
return;
}

之后返回process（）调用process1（），此时向量大小再次为0：

void PPM::process1()
{
// for each pixel {
//   find  closest qcolor 
//   set pixel color to closest qcolor
// }
cerr << "img size: " << img.size() << '\n';
cerr << "qcolor size: " << qcolors.size() << '\n';

float distance, min_distance;
int min_index;

//go thru each element in the vector of the img pixels
for (int i=0; i<img.size(); i++) {
    for (int j=0; i<qcolors.size(); j++) {
        distance = img[i].distance(qcolors[j]);
        cerr << "calced distance of " << distance << '\n';
        if (distance < min_distance || j == 1) {
            min_distance = distance;
            min_index = j;
            cerr << "set min distance to " << min_distance << '\n';
        }
    }
    img[i] = qcolors[min_index];
}

return;
}

Answer 1

您似乎在隐藏您的成员变量（在read_qcolors中）：

vector <RGB> qcolors;

在这种情况下只需删除此行，它将使用成员变量。

退出功能后，矢量大小变为0

1 个答案: