c++ - 有条件地逐行读取文件

Question

现在我有代码:

if (minimizator_weighted) {
    while (dataFile >> t >> e >> sigma) { // read data file value by value
        /* some code */
    }
}
else {
    while (dataFile >> t >> e) { // all the same but will not read standard deviation
        /* almost the same code */
    }
}

如您所见，if 和 else 流程之间的唯一区别是 while 循环的条件。我想知道是否有可能优化该代码段并重新使用代码？如果我能写一些这样的东西就好了:

while ((minimizator_weighted) ? (dataFile >> t >> e >> sigma) : (dataFile >> t >> e)) { ... }

但我不确定这个技巧是否正确......你能给我一些优化建议吗？谢谢!

编辑这是完整的代码片段

if (minimizator_weighted) {
    while (dataFile >> t >> e >> sigma) { // read data file value by value
        data_set::pt point;
        point.t = t;
        point.e = e;
        point.c_vis = 0.0;
        point.c_invis = 0.0;

        if (std::abs(sigma) <= GSL_SQRT_DBL_MIN) // check for division-by-zero error
            sigma = 1.0;

        point.sigma = sigma;

        set.curve.push_back(point); // store point

        data_numPoints++; // collect some stats
        set.curveAvg += e;
    }   
}   
else {
    while (dataFile >> t >> e) { // all the same but will not read standard deviation
        data_set::pt point;
        point.t = t;
        point.e = e;
        point.c_vis = 0.0;
        point.c_invis = 0.0;

        set.curve.push_back(point);

        data_numPoints++;
        set.curveAvg += e;
    }   
}

Answer 1

添加一个间接级别

bool read_data_line1(istream& dataFile, T& t, E& e, Sig& sigma)
{ return dataFile >> t >> e >> sigma; }

bool read_data_line2(istream& dataFile, T& t, E& e, Sig&)
{ return dataFile >> t >> e; }

auto read_data_line_func = minimizator_weighted ? read_data_line1 : read_data_line2;
while(read_data_line_func(dataFile, t, e, sigma))
{
    data_set::pt point;
    point.t = t;
    point.e = e;
    point.c_vis = 0.0;
    point.c_invis = 0.0;

    if (minimizator_weighted)
    {
      if (std::abs(sigma) <= GSL_SQRT_DBL_MIN) // check for division-by-zero error
        sigma = 1.0;
      point.sigma = sigma;
    }

    set.curve.push_back(point); // store point

    data_numPoints++; // collect some stats
    set.curveAvg += e;
}