C makes no distinction between a variable identifier and a constant identifier. However, it is often useful to know whether the identifier you are using is a constant.
As with functions and variables, there are several conventions commonly used for naming constants. The following conventions are relatively common to arbitrarily differentiate constants from variables:
- Prefix a constant name with k or k_—for example, kInchesPerFoot or k_inches_per_foot.
- Suffix a name with const or _const—for example, inchesPerFootConst or inches_per_foot_const.
- Use snake-case with all the capitals—for example, THIS_IS_A_CONSTANT. All-uppercase is quite unreadable. This is typically used for the #define symbols to show that they are not just a constant—for example, INCHES_PER_FOOT.
- None. C does not distinguish between constants—for example, int inchesPerFoot versus const int inchesPerFoot...
