The choice of character set significantly impacts the size of data stored in a file. Character sets with fewer bits per character (like ASCII) require less storage space than character sets with more bits per character (like Unicode). This is because each character is represented by a different number of bytes.
Example: Consider the string "Hello".
ASCII Encoding: Each character in "Hello" can be represented using 7 bits. Therefore, the string requires 5 characters * 7 bits/character = 35 bits. Since bits are typically stored in bytes (8 bits), this translates to 35 bits / 8 bits/byte = 4.375 bytes. In practice, this would be rounded up to 5 bytes.
UTF-8 Encoding: UTF-8 is a variable-length encoding. ASCII characters (like 'H', 'e', 'l', 'o') are represented by a single byte. However, some characters (e.g., accented characters like 'é') require multiple bytes. In the case of "Hello", each character is represented by a single byte, so the string requires 5 bytes.
UTF-16 Encoding: UTF-16 uses 2 bytes per character. Therefore, "Hello" would require 5 characters * 2 bytes/character = 10 bytes.
This example demonstrates that using a more compact character set like ASCII can reduce the storage space required for text data, while using a more comprehensive character set like UTF-16 can increase the storage space. The choice depends on the requirements of the application, considering factors like the range of characters that need to be supported and the available storage space.