PROCEDURES(过程) When a procedure is called, the body is executed. Each execution of the body is called an activation of the body. Two forms of procedures: functions Functions extend the built-in operators of a language. procedures Procedures extend the built-in actions or statementsPROCEDURES（过程） When a procedure is called, the body is executed. Each execution of the body is called an activation of the body. Two forms of procedures: • functions Functions extend the built-in operators of a language. • procedures Procedures extend the built-in actions or statements