A statement is a command that is executed for effect. A computer takes input, processes the input, and produces output.

• input: input statements
• processing: assignment statements
• output: output statements

Primitive statements are input, assignment, and output.

In any programming language, the only statements that do anything (have any effect) are the following.

• input
• assignment
• output

All other statements control which of the primitive statements get executed (for effect) and in what order and under what contritions.