Building Blockchain Projects

Visibility

The visibility of a state variable or a function defines who can see it. There are four kinds of visibilities for function and state variables: external, public, internal, and private.

By default, the visibility of functions is public and the visibility of state variables is internal. Let's look at what each of these visibility functions mean:

• external: External functions can be called only from other contracts or via transactions. An external function f cannot be called internally; that is, f() will not work, but this.f() works. You cannot apply the external visibility to state variables.
• public: Public functions and state variables can be accessed in all ways possible. The compiler generated accessor functions are all public ...