Can the offset used in the fseek() function be a negative number?

The offset used in the fseek() function can indeed be a negative number. This allows the function to move the file pointer backwards in the file. The fseek() function takes three arguments: a file pointer, an offset, and a starting point defined by a constant such as SEEK_SET, SEEK_CUR, or SEEK_END.

When the offset is negative and the starting point is set to SEEK_CUR, for instance, the file pointer moves backward from its current position, allowing for flexible navigation within the file's data. This can be useful for scenarios where you need to reposition the file pointer in relation to where you are currently located in the file.

It's important to ensure that the resulting position after applying the negative offset does not point before the beginning of the file, as this would lead to undefined behavior, but the ability to use a negative offset itself is legitimate and valid.