C++ Input and Output I/O

In C++, input and output operations are performed using the cin and cout streams.

Standard Output (cout)

The standard output in C++ is represented by the cout stream. The cout stream is used to output data to the screen. The cout stream is declared in the iostream library, and it is used along with the insertion operator <<.

Here's an example of using cout to output data to the screen:

1#include <iostream>
2
3int main()
4{
5    std::cout << "Hello World!" << std::endl;
6    return 0;
7}

In the above code, the text "Hello World!" is output to the screen using the cout stream and the insertion operator <<. The std::endl manipulator is used to insert a newline character after the output.

Standard Input (cin)

The standard input in C++ is represented by the cin stream. The cin stream is used to input data from the keyboard. The cin stream is also declared in the iostream library, and it is used along with the extraction operator >>.

Here's an example of using cin to input data from the keyboard:

1#include <iostream>
2
3int main()
4{
5    int x;
6    std::cout << "Enter a number: ";
7    std::cin >> x;
8    std::cout << "You entered: " << x << std::endl;
9    return 0;
10}

In the above code, the user is prompted to enter a number using the cout stream. The input is then stored in the variable x using the cin stream and the extraction operator >>. The input value is then output to the screen using the cout stream.

using namespace std

Include using namespace std; statement at top to avoid using cin and count without std::

1#include <iostream>
2using namespace std;
3
4int main()
5{
6    int x;
7    cout << "Enter a number: ";
8    cin >> x;
9    cout << "You entered: " << x << endl;
10    return 0;
11}

In the above example, the line using namespace std; allows us to use the cin and cout streams without having to qualify them with std::. This line makes all the symbols in the std namespace available to our code.