STL: Containers

76. Use vector by default. Otherwise, choose an appropriate container.

Using the "right container" is great: If you have a good reason to use a specific container type, use that container type knowing that you did the right thing.

So is using vector: Otherwise, write vector and keep going without breaking stride, also knowing you did the right thing.

77. Use vector and string instead of arrays.

Why juggle Ming vases? Avoid implementing array abstractions with C-style arrays, pointer arithmetic, and memory management primitives. Using vector or string not only makes your life easier, but also helps you write safer and more scalable software.

78. Use vector (and string::c_str) to exchange data with non-C++ APIs.

vector isn't lost in translation: vector and string::c_str are your gateway to communicate with non-C++ APIs. But don't assume iterators are pointers; to get the address of the element referred to by a vector<T>::iterator iter, use &*iter.

79. Store only values and smart pointers in containers.

Store objects of value in containers: Containers assume they contain value-like types, including value types (held directly), smart pointers, and iterators.

80. Prefer push_back to other ways of expanding a sequence.

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.

81. Prefer range operations to single-element operations.

Don't use oars when the wind is fair (based on a Latin proverb): When adding elements to sequence containers, prefer to use range operations (e.g., the form of insert that takes a pair of iterators) instead of a series of calls to the single-element form of the operation. Calling the range operation is generally easier to write, easier to read, and more efficient than an explicit loop. (See alsoItem 84.)

82. Use the accepted idioms to really shrink capacity and really erase elements.

Use a diet that works: To really shed excess capacity from a container, use the "swap trick." To really erase elements from a container, use the erase-remove idiom.