Abseil.io

Why Write Tests

The later a bug is caught in the development cycle, the more expensive it is to fix it. A good test today is a future debugging session saved.

The test is the first client of your code. It uncovers sub-optimal design choices, tight couplings, missed cases, etc..

Unscoped (or Plain or C-Style) Enumerations

Plain (or C-style) enums are entered in the same scope as the name of their enum, and implicitly convert to their integer value, e.g.

enum Color { red, green, blue };
int col = green;
Color c2 = 1; // error: invalid conversion from 'int' to 'Color' [-fpermissive]

enum CardColor { red, black }; // Error: "red" conflicts with a previous declaration

The name can be omitted if it’s not going to be used, e.g.

enum { red, green, blue };
int col = red;

.

Unnamed enums are common in code written before alternative ways of specifying integer constants, e.g.

Resource Handles

The constructor/destructor pattern enables objects defined in a scope to release the resources during exit from the scope, even when exceptions are thrown. All standard-library containers, e.g. std::vector, are implemented as resource handles.

std::unique_ptr and std::shared_ptr

These “smart pointers” are useful in managing objects that are allocated on the free store (as opposed to those allocated on the stack).

A class is a user-defined type provided to represent a concept in the code of a program. Essentially, all language facilities beyond the fundamental types, operators, and statements exist to help define better class or to use them more conveniently.