The C Standard Library

C++ Library - <spanstream>

The <spanstream> header is used for the input and output operations within the C++ standard library. This header provides a way to manipulate the input and output streams using spans, which are contiguous sequences of elements.

The <spanstream> is used in scenarios where data is being read from or written to various formats. It provides a set of functions that allow for conversion, the commonly used C++ <spanstream> functions are listed below along with their description.

Including <spanstream> Header

To include the <spanstream> header in your C++ program, you can use the following syntax.

#include <spanstream>

Functions of <spanstream> Header

Below is list of all functions from <spanstream> header.

Sr.No	Functions & Description
1	operator= It move-assignments the spanstream.
2	swap It swaps two spanstream objects.
3	rdbuf It obtains the address of the wrapped raw span device object.
4	span It gets or sets the underlying buffer of the wrapped span device object.
5	setbuf It attempts to replace the controlled character sequence with an array.
6	seekoff It repositions the next pointer in the input sequence, output sequence, or both, using relative addressing.
7	seekpos It repositions the next pointer in the input sequence, output sequence, or both using absolute addressing.

Inserting a Character

In the following example, we are going to use the put() to insert a single character into the stream.

#include <spanstream>
#include <iostream>
#include <span>
int main() {
   char a[5];
   std::ospanstream os(a);
   os.put('X');
   os.put('Y');
   std::cout << "Result : " << a << std::endl;
   return 0;
}

Output

Output of the above code is as follows −

Result : XY

Reading the Characters

Consider the following example, where we are going to use the read() to read the characters.

#include <spanstream>
#include <iostream>
#include <span>
int main() {
   char a[] = "Welcome";
   std::ispanstream is(a);
   char x[8];
   is.read(x, 3);
   x[3] = '\0';
   std::cout << "Result : " << x << std::endl;
   return 0;
}

Output

Following is the output of the above code −

Result : Wel

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