C++ 如何在输出控制台中显示更多小数？

How do I display more decimals in the output console?

提问by Faken

I want to output the value of a double in it's full precision. However, when using the cout function, it only displays the first 6 digits even though there is around 15-16 digits of precision.

我想以全精度输出双精度值。然而，当使用 cout 函数时，它只显示前 6 位数字，即使有大约 15-16 位的精度。

How do I get my program to display the entire value, including the magnitude (power) component?

如何让我的程序显示整个值，包括幅度（功率）分量？

回答by Amber

Use the setprecision()manipulator:

使用setprecision()操纵器：

http://www.cplusplus.com/reference/iostream/manipulators/setprecision/

http://www.cplusplus.com/reference/iostream/manipulators/setprecision/

You can also force scientific notation with the scientificmanipulator:

您还可以使用scientific操纵器强制使用科学记数法：

http://www.cplusplus.com/reference/iostream/manipulators/scientific/

http://www.cplusplus.com/reference/iostream/manipulators/scientific/

cout << scientific << setprecision(15) << my_number << endl;

回答by Indy9000

you could use something like this :

你可以使用这样的东西：

#include <iomanip>

cout << setprecision (9) << double_value << endl;

more iomanipulators, here

更多的iomanipulators，在这里

回答by Sam Harwell

You're looking for setprecision(code taken from link):

您正在寻找setprecision（来自链接的代码）：

int main () {
  double f =3.14159;
  cout << setprecision(15) << f << endl;
  return 0;
}