C++ Coding Standards: 101 Rules, Guidelines, and Best Practices

80. Prefer push_back to other ways of expanding a sequence

Summary

push_back all you can: If you don’t need to care about the insert position, prefer using push_back to add an element to sequence. Other means can be both vastly slower and less clear.

Discussion

You can insert elements into sequences at different points using insert, and you can append elements to sequences in various ways including:

Of all forms, push_back alone takes amortized constant time. The other forms’ performance can be as bad as quadratic. Needless to say, beyond small data volumes that makes those alternatives potential scalability barriers. (See Item 7.)

push_back ...