ios manipulators nounitbuf() function in C++

Last Updated : 12 Jul, 2025
The nounitbuf() method of stream manipulators in C++ is used to clear the showbase format flag for the specified str stream. This flag does not flushes the associated buffer after each operation. Syntax:
ios_base& nounitbuf (ios_base& str)
Parameters: This method accepts str as a parameter which is the stream for which the format flag is to be cleared. Return Value: This method returns the stream str with nounitbuf format flag set. Example 1: CPP
// C++ code to demonstrate
// the working of nounitbuf() function

#include <iostream>
#include <sstream>

using namespace std;

int main()
{

    // Initializing the character
    char a, b, c;

    // Stream input with leading whitespaces
    istringstream iss("GFG");

    // Using nounitbuf()
    iss >> nounitbuf >> a >> b >> c;

    cout << "nounitbuf flag: "
         << a << endl
         << b << endl
         << c << endl;

    return 0;
}
Output:
nounitbuf flag: G
F
G
Example 2: CPP
// C++ code to demonstrate
// the working of nounitbuf() function

#include <iostream>
#include <sstream>

using namespace std;

int main()
{

    // Initializing the character
    char a, b, c, d, e;

    // Stream input with leading whitespaces
    istringstream iss("GEEKS");

    // Using nounitbuf()
    iss >> nounitbuf >> a >> b >> c >> d >> e;

    cout << "nounitbuf flag: "
         << a << endl
         << b << endl
         << c << endl
         << d << endl
         << e << endl;

    return 0;
}
Output:
nounitbuf flag: G
E
E
K
S
Reference: https://cplusplus.com/reference/ios/nounitbuf/
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