swapping bytes in a file in c++ [closed]

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered i开发者_如何学Pythonn its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 12 years ago.

assume that there is a file named "swaplt.doc" which contains more than 200bytes of data.now write a program that will encrypt the file by swapping its first 100 bytes of data with last 100 bytes.

---

1. Read the file into memory
2. Modify the memory
3. Write the memory back to file

---

1. Create two buffers of length 100 bytes each, say A and B.
2. Read 100 bytes from file to A (assuming that the file cursor points to the beginning of the file).
3. Seek to file length n-100.
4. Read 100 bytes from file to B.
5. Again, seek to file length n-100.
6. Write 100 bytes from A to file.
7. Seek to file position 0.
8. Write 100 bytes from B to file.