ios clear() function in C++ with Examples

The clear() method of ios class in C++ is used to change the current state of the specified flag by setting it. Hence this function changes the internal state of this stream.

Syntax:

void clear(iostate state)

Parameters: This method accepts the iostate as parameter which is the flag bit to be set in this stream. It can be goodbit, failbit, eofbit or badbit.

Return Value: This method do not return anything.

Example 1:

// C++ code to demonstrate
// the working of clear() function

#include <bits/stdc++.h>
using namespace std;

int main()
{

    // Stream
    stringstream ss;

    // Print the result
    cout << "is failbit set: "
         << ss.fail() << endl;

    // Using clear() function
    ss.clear(ss.failbit);

    cout << "clear() used to set failbit "
         << endl;

    // Print the result
    cout << "is failbit set: "
         << ss.fail() << endl;

    return 0;
}

Output:

is eofbit set: 0
clear() used to set eofbit 
is eofbit set: 1

Example 2:

Output:

is failbit set: 0
clear() used to set failbit 
is failbit set: 1

Reference: hhttp://www.cplusplus.com/reference/ios/ios/clear/