以更精确的方式将数字写入文件 - C ++ [英] Writing numbers to a file with more precision - C++

问题描述

我写了一些参数（所有类型 double ）到一个文件，用于执行一些复杂的计算。我写的参数到文件像这样：

I wrote some parameters (all of type double) to a file for use in performing some complex computations. I write the parameters to the files like so:

refStatsOut< SomeParam：< value_of_type_double< endl;

其中 refStatsOut 是 ofstream 参数。有四个这样的参数，每个类型 double 。我看到写入文件与其实际值不同（在精度损失方面）。例如，如果 value_of_type_double 的值为-28.07270379934792，那么我在文件中看到的是-28.0727。

refStatsOut << "SomeParam:" << value_of_type_double << endl;
where refStatsOut is an ofstreamparameter. There are four such parameters, each of type double. What I see as written to the file is different from what its actual value is (in terms of loss of precision). As an example, if value_of_type_double had a value -28.07270379934792, then what I see as written in the file is -28.0727.

此外，一旦计算和编写了这些统计数据，我运行使用这些统计信息的不同程序。文件被读取，并且值最初存储为 std :: strings ，然后通过<$ c转换为 double $ c> atof 函数。这导致我在上面显示的值，并进一步废除计算。

Also, once these stats have been computed and written I run different programs that use these statistics. The files are read and the values are initially stored as std::strings and then converted to double via atof functions. This results in the values that I have shown above and ruins the computations further down.

我的问题是这样：

1.是否有办法增加可以写入值的分辨率（ double 等）到一个文件，以便不会丢失任何精度？

2.这也可能是一个问题 std ::字符串到 double 转换 atof ？如果是这样，我可以使用什么其他功能来解决这个问题？

My question is this:
1. Is there a way to increase the resolution with which one can write values (of type double and the like) to a file so as to NOT lose any precision?
2. Could this also be a problem of std::string to double conversion with atof? If so, what other function could I use to solve this?

P.S：请让我知道这个问题的一些细节不清楚。

P.S: Please let me know in case some of the details in this question are not clear. I will try to update them and provide more details.

推荐答案

您可以使用 setprecision 函数。

You can use the setprecision function.

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