The meaning of & ldquo; const & rdquo; in a declaration of function
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The meaning of & ldquo; const & rdquo; in a declaration of function
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I have a function with 3 const's in it:
const std::string at(const unsigned int index) const;
To my understanding, the parameter (const unsigned int index ) means that index will not be changed. What about the other two const's? Why are they there?
The const keywoard in C++ indicates that a particular object or variable is not modifiable. It can be used in various contexts:
Const variables
Declaring a variable as const inside of a function indicates that the variable will not be modified inside the function.
Const member functions
Declaring a member function as const, which is done by appending const to the end of the function prototype, indicates that the function is a "read-only" function that does not modify the object for which it is called.
The rule for const viability is that const-ness can be applied to a non-const variable or member function, but once applied it cannot be removed.
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