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Output String (cout.write()) in C++

The std::ostream::write() member function is used to output a character sequence (a C-style string or a part of a string) to the standard output (console). It is often used with std::cout, which is an instance of std::ostream. In this tutorial, we'll learn how to use cout.write() to output a string in C++.

Include necessary headers:

To use std::cout and cout.write(), you need to include the <iostream> header:

#include <iostream>

Use cout.write() to output a C-style string:

Here's an example of using cout.write() to output a C-style string:

int main() {
    const char* text = "Hello, World!";

    // Output the string using cout.write()
    std::cout.write(text, 13);

    return 0;
}

In this example, we first create a C-style string containing the text "Hello, World!". We then use cout.write() to output the string by specifying the pointer to the character array (text) and the number of characters to output (13 in this case).

Use cout.write() to output part of a string:

You can also use cout.write() to output only a part of a string:

#include <string>

int main() {
    std::string text = "Hello, World!";

    // Output the first 5 characters of the string using cout.write()
    std::cout.write(text.c_str(), 5);

    return 0;
}

In this example, we first create a std::string containing the text "Hello, World!". We then use cout.write() to output the first 5 characters of the string by specifying the pointer to the underlying character array (text.c_str()) and the number of characters to output (5 in this case).

Example: Output a string with a null character in the middle:

Here's an example that demonstrates how to use cout.write() to output a string containing a null character in the middle:

#include <iostream>
#include <string>

int main() {
    std::string text = "Hello\0, World!"; // A string containing a null character

    // Output the whole string, including the null character, using cout.write()
    std::cout.write(text.c_str(), text.size());

    return 0;
}

In this example, we first create a std::string containing the text "Hello\0, World!", which has a null character in the middle. We then use cout.write() to output the whole string, including the null character, by specifying the pointer to the underlying character array (text.c_str()) and the number of characters to output (text.size() in this case).

That's it for our tutorial on using cout.write() to output a string in C++. By using cout.write(), you can output character sequences to the standard output, allowing you to have more control over the console output in your C++ programs.

How to Output a String with cout.write() in C++:

cout.write() is used to output a sequence of characters from a string.

Example:

#include <iostream>

int main() {
    const char* myString = "Hello, World!";
    std::cout.write(myString, 13);  // Output the first 13 characters
    return 0;
}

Using cout.write() for String Output in C++:

cout.write() is specifically designed for writing a specified number of characters from a string.

Example:

#include <iostream>

int main() {
    const char* myString = "Hello, World!";
    std::cout.write(myString, 7);  // Output the first 7 characters
    return 0;
}

String Stream Output with cout.write() in C++:

cout.write() is part of the standard output stream and can be used in combination with other stream operations.

Example:

#include <iostream>
#include <sstream>

int main() {
    std::ostringstream oss;
    oss << "This is a ";
    std::cout.write(oss.str().c_str(), 10);  // Output the first 10 characters
    return 0;
}

String Formatting with cout.write() in C++:

Formatting can be applied before using cout.write() for string output.

Example:

#include <iostream>
#include <iomanip>

int main() {
    const char* myString = "Formatted";
    std::cout << std::setw(10) << std::left << std::setfill('*');
    std::cout.write(myString, 6);  // Output the first 6 characters
    return 0;
}

Examples of cout.write() for String Output in C++:

Outputting substrings and portions of strings.

Example:

#include <iostream>

int main() {
    const char* myString = "abcdef";
    std::cout.write(myString + 1, 3);  // Output characters from index 1 to 3
    return 0;
}

Handling Newline and Special Characters with cout.write() in C++:

Special characters can be included in the string passed to cout.write().

Example:

#include <iostream>

int main() {
    const char* myString = "New\nLine";
    std::cout.write(myString, 9);  // Output the first 9 characters
    return 0;
}

String Buffering and cout.write() in C++:

C++ uses buffering for output. cout.write() contributes to the buffer.

Example:

#include <iostream>

int main() {
    const char* myString = "Buffered";
    std::cout.write(myString, 7);  // Contributes to the output buffer
    std::cout.flush();  // Flush the buffer to ensure immediate output
    return 0;
}

Flushing the Output Buffer with cout.write() in C++:

The flush() function can be used to flush the output buffer.

Example:

#include <iostream>

int main() {
    const char* myString = "Flush";
    std::cout.write(myString, 5).flush();  // Flushes the buffer
    return 0;
}

Unicode and Wide String Output with cout.write() in C++:

For Unicode or wide string output, consider using wide streams (wcout.write()).

Example:

#include <iostream>
#include <cwchar>

int main() {
    const wchar_t* myWideString = L"\u03A9 Unicode";
    std::wcout.write(myWideString, 8);  // Output the first 8 characters
    return 0;
}

Customizing String Output with cout.write() in C++:

Customize string output using manipulators and formatting.

Example:

#include <iostream>
#include <iomanip>

int main() {
    const char* myString = "Customize";
    std::cout << std::setw(10) << std::left << std::setfill('*');
    std::cout.write(myString, 8);  // Output the first 8 characters
    return 0;
}