C++ streambuf::sputn() function

The C++ std::streambuf::sputn() function is used to write a sequence of characters to a buffer. It writes the specified number of characters from a given memory location to the stream buffer. It returns the number of characters successfully written.

Syntax

Following is the syntax for std::streambuf::sputn() function.

streamsize sputn (const char* s, streamsize n);

Parameters

• s − It indicates the pointer to the sequence of characters to be written.
• n − It indicates the number of characters to write.

Return Value

It returns the number of characters written.

Exceptions

If an exception is thrown, the stream buffer is in a valid state.

Data races

It modifies the stream buffer object.

Example 1

In the following example, we are going to consider the basic usage of the sputn() function.

#include <iostream>
#include <sstream>
int main() {
   std::stringbuf x;
   const char * y = "TP";
   x.sputn(y, 2);
   std::cout << x.str() << std::endl;
   return 0;
}

Output

Output of the above code is as follows −

TP

Example 2

Consider the following example, where we are going to write the part of the string.

#include <iostream>
#include <sstream>
int main() {
   std::stringbuf x;
   const char * y = "Hi, Welcome";
   x.sputn(y, 2);
   std::cout << x.str() << std::endl;
   return 0;
}

Output

Following is the output of the above code −

Hi