Why is reading lines from stdin much slower in C++ than Python?

Reading from stdin can be slower in C++ than in Python for a few reasons:

1. In C++, stdin is typically buffered, meaning that the input is not read one character at a time, but rather in larger blocks. This can make reading from stdin slower, especially if the input is coming from a slow source such as a terminal or a pipe.

2. C++ streams are generally slower than Python's built-in I/O functions because they provide more functionality and perform additional error checking.

3. Python's interpreter can optimize certain I/O operations by reading input in larger chunks and buffering it in memory, which can make reading from stdin faster in some cases.

There are ways to make reading from stdin faster in C++, such as using unbuffered streams or reading the input directly into a buffer using the read function from the <unistd.h> header. However, these methods are more complex and may not be appropriate for all situations.