String Stream Constructors

Syntax:

    #include 
stringstream()
stringstream( openmode mode )
stringstream( string s, openmode mode )
ostringstream()
ostringstream( openmode mode )
ostringstream( string s, openmode mode )
istringstream()
istringstream( openmode mode )
istringstream( string s, openmode mode )

The stringstream, ostringstream, and istringstream objects are used for input and output to a string. They behave in a manner similar to fstream, ofstream and ifstream objects. The optional mode parameter defines how the file is to be opened, according to the io_stream_mode_flags. An ostringstream object can be used to write to a string. This is similar to the C sprintf() function. For example:

    ostringstream s1;
int i = 22;
s1 << "Hello " << i << endl;
string s2 = s1.str();
cout << s2;

An istringstream object can be used to read from a string. This is similar to the C sscanf() function. For example:

    istringstream stream1;
string string1 = "25";
stream1.str(string1);
int i;
stream1 >> i;
cout << i << endl; // displays 25

You can also specify the input string in the istringstream constructor as in this example:

    string string1 = "25";
istringstream stream1(string1);
int i;
stream1 >> i;
cout << i << endl; // displays 25

A stringstream object can be used for both input and output to a string like an fstream object.

Related Topics: C++ I/O streams

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