How to open a file for both reading and writing?
Summarize the I/O behaviors
| Mode | r | r+ | w | w+ | a | a+ || :--------------------: | :--: | :--: | :--: | :--: | :--: | :--: || Read | + | + | | + | | + || Write | | + | + | + | + | + || Create | | | + | + | + | + || Cover | | | + | + | | || Point in the beginning | + | + | + | + | | || Point in the end | | | | | + | + |
and the decision branch