Home  >  Article  >  Backend Development  >  How to achieve precise formatting with std::ostream like printf_s?

How to achieve precise formatting with std::ostream like printf_s?

Linda Hamilton
Linda HamiltonOriginal
2024-10-30 04:30:28274browse

How to achieve precise formatting with std::ostream like printf_s?

Precise Formatting with std::ostream

How to achieve precise formatting with std::cout? Consider the following example:

<code class="cpp">double my_double = 42.0;
char str[12];
printf_s("%11.6lf", my_double); // Prints " 42.000000"</code>

In this code, printf_s is used to format and print the double my_double with specific precision and width. The equivalent functionality in std::ostream can be achieved using stream manipulators.

To output " 42.000000" using std::cout, apply these manipulators in sequence:

std::fixed: Sets fixed-point notation instead of scientific notation.

std::setw(11): Sets the width of the output field to 11 characters.

std::setprecision(6): Specifies the number of digits to be displayed after the decimal point.

The correct code becomes:

<code class="cpp">#include <iomanip>

std::cout << std::fixed << std::setw(11) << std::setprecision(6) << my_double;</code>

This approach allows for precise formatting of double values using std::ostream without resorting to third-party libraries or custom string manipulation.

For a comprehensive reference on std::ostream formatting, refer to the C Standard Library documentation, specifically the section on "Stream Manipulators."

The above is the detailed content of How to achieve precise formatting with std::ostream like printf_s?. For more information, please follow other related articles on the PHP Chinese website!

Statement:
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn