Characteristic elements in the design of a loop

initialization
while (condition) {
  operation
  next step
}

• initialization: sets the variables used in the loop before starting the execution of the loop (before the loop statement)
  E.g., product = 0;
• condition: expression evaluated at the beginning of each iteration, whose truth value determines whether the body of the loop is executed or whether the loop finishes
  E.g., (multiplicator > 0)
• operation of the loop: computation of the partial result at each loop iteration (in the body of the loop)
  E.g., product = product + multiplicand;
• next step: increment/decrement operation for the variable that controls the repetitions of the loop (in the body of the loop)
  E.g., multiplicator--;

Once we have designed the loop, we have to check its proper termination. In particular, we have to check that the execution of the loop statements can modify the value of the condition in such a way that it becomes false.

Example: The statement multiplicator--; can cause the condition (multiplicator > 0) to become false, provided multiplicator is a positive integer number.