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idealvin / coost

A tiny boost library in C++11.
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浮点数转字符串没有四舍五入？ #333

Open cailei77 opened 1 year ago

cailei77 commented 1 year ago

double f = 3.14159265; fastring str; str << dp::_n(f, 4); cout << str << std::endl; 这段代码输出的结果是3.1415，按照精度要求应该是3.1416吧？

youngday commented 12 months ago

if we convert rad to degree, rang will over 180, 180.0004, you can use round ,floor, or ceil ,before string conversion.

cailei77 commented 12 months ago

if we convert rad to degree, rang will over 180, 180.0004, you can use round ,floor, or ceil ,before string conversion. 我只是说浮点数转换为字符串的显示精度问题，计算精度应该不受影响

idealvin commented 12 months ago

double f = 3.14159265; fastring str; str << dp::_n(f, 4); cout << str << std::endl; 这段代码输出的结果是3.1415，按照精度要求应该是3.1416吧？

现在没有考虑四舍五入