4.8. Nested Control Statements

We’ve seen that control statements can be stacked on top of one another (in sequence). Here, we examine the only other structured way control statements can be connected, namely, by nesting one control statement within another. Consider the following problem statement:

A college offers a course that prepares students for the state licensing exam for real estate brokers. Last year, ten of the students who completed this course took the exam. The college wants to know how well its students did on the exam. You’ve been asked to write a program to summarize the results. You’ve been given a list of these 10 students. Next to each name is written a 1 if the student passed the exam or a 2 if the student failed.

Your program should analyze the results of the exam as follows:

1. Input each test result (i.e., a 1 or a 2). Display the prompting message “Enter result” each time the program requests another test result.

2. Count the number of test results of each type.

3. Display a summary of the test results indicating the number of students who passed and the number who failed.

4. If more than eight students passed the exam, print the message “Bonus to instructor!”

After reading the problem statement carefully, we make the following observations:

1. The program must process test results for 10 students. A counter-controlled loop can be used because the number of test results is known in advance.

2. Each test result is a number—either a 1 or a 2. Each time the program reads a test result, the program must determine whether the number is a 1 or a 2. For simplicity, we test only for a 1 in our algorithm. If the number is not a 1, we assume that it’s a 2.

3. Two counters are used to keep track of the exam results—one to count the number of students who passed the exam and one to count the number of students who failed the exam.

4. After the program has processed all the results, it must decide whether more than eight students passed the exam.