c++ - 在 C++ 中使用 boost::lexical_cast 将 double 转换为字符串？

Question

我想使用 lexical_cast 将 float 转换为字符串。通常它工作正常，但我对没有小数的数字有一些问题。如何修复字符串中显示的小数位数？

例子:

double n=5;
string number;
number = boost::lexical_cast<string>(n);

结果编号是5，我需要编号5.00。

Answer 1

来自 boost lexical_cast 的文档:

For more involved conversions, such as where precision or formatting need tighter control than is offered by the default behavior of lexical_cast, the conventional stringstream approach is recommended. Where the conversions are numeric to numeric, numeric_cast may offer more reasonable behavior than lexical_cast.

例子:

#include <sstream>
#include <iomanip>

int main() {
    std::ostringstream ss;
    double x = 5;
    ss << std::fixed << std::setprecision(2);
    ss << x;
    std::string s = ss.str();
    return 0;
}