examples/variables/declare/input.md - rust-by-example - Git at Google

 It's possible to declare variables first, and initialize them later. But, this
 form is seldom used, as it may lead to the use of uninitialized variables.

 {declare.play}

 The compiler forbids use of uninitialized variables, as this would lead to
 undefined behavior.
	It's possible to declare variables first, and initialize them later. But, this
	form is seldom used, as it may lead to the use of uninitialized variables.

	{declare.play}

	The compiler forbids use of uninitialized variables, as this would lead to
	undefined behavior.