What does iomanip mean in c language

The iomanip library is used in C for formatted input and output operations, specifying how to format the data through format flags. It provides the following functions: formatting input, reading data from the input stream. Format output, writes data to the output stream and formats it as specified. Use format flags such as setw(n) (set field width), setprecision(n) (set decimal places), and setiosflags(flag) (set I/O stream flags).

The meaning of iomanip in C language

iomanip is used for input and output in the C standard library (I /O) library for operations. It provides formatting functions for the following operations:

• Input: Allows the user to read formatted data from an input stream (such as keyboard input).
• Output: Writes data to an output stream (such as the console or a file) and formats it in the specified format.

The iomanip library implements formatting through the use of format flags, which specify how to format the data. For example:

• setw(n): Set field width (n characters).
• setprecision(n): Set the number of decimal places (n digits) for floating point numbers.
• setiosflags(flag): Set the flags of the I/O stream, such as ios::fixed (fixed decimal point notation) and ios::left (left alignment).

Usage example:

<code class="cpp">// 输出一个宽度为 10 个字符、小数点后保留 2 位小数的浮点数
cout << setw(10) << setprecision(2) << 123.456;</code>

Output:

<code>    123.46</code>

Note:

• In C, the iomanip library is located in the std namespace, so you need to use std::iomanip to access its functions.
• To use iomanip, you need to include the <iomanip> header file.

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