Home > Articles > Programming > C/C++

Like this article? We recommend

4.8 Nested Control Statements

In this case study, 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 have been asked to write a program to summarize the results. You have 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 "Raise tuition."

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.
  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.

Conversion to Class Analysis

The C++ class, Analysis, in Fig. 4.12–Fig. 4.13, solves the examination results problem—two sample executions appear in Fig. 4.14.

Fig. 4.12 Examination-results problem: Analysis header file.

 1  // Fig. 4.12: Analysis.h
 2  // Definition of class Analysis that analyzes examination results.
 3  // Member function is defined in Analysis.cpp
 4
 5  // Analysis class definition
 6  class Analysis
 7  {
 8  public:
 9           void processExamResults(); // process 10 students' examination results
10  }; // end class Analysis

               

Fig. 4.13 Examination-results problem: Nested control statements in Analysis source code file.

 1  // Fig. 4.13: Analysis.cpp
 2  // Member-function definitions for class Analysis that
 3  // analyzes examination results.
 4  #include <iostream>
 5  using std::cout;
 6  using std::cin;
 7  using std::endl;
 8
 9  // include definition of class Analysis from Analysis.h
10  #include "Analysis.h"
11
12  // process the examination results of 10 students
13  void Analysis::processExamResults()
14  {
15     // initializing variables in declarations 
16     int passes = 0; // number of passes       
17     int failures = 0; // number of failures   
18     int studentCounter = 1; // student counter
19     int result; // one exam result (1 = pass, 2 = fail)
20
21     // process 10 students using counter-controlled loop
22     while ( studentCounter <=  10  )
23     {
24         // prompt user for input and obtain value from user
25         cout << "Enter result (1 = pass, 2 = fail): ";
26         cin >> result; // input result
27
28         // if...else nested in while                           
29         if ( result == 1 )          // if result is 1,         
30              passes = passes + 1;  // increment passes;       
31         else                        // else result is not 1, so
32           failures = failures + 1; // increment failures      
33
34         // increment studentCounter so loop eventually terminates
35         studentCounter = studentCounter + 1;
36      } // end while
37
38      // termination phase; display number of passes and failures
39      cout << "Passed " << passes << "\nFailed " << failures << endl;
40
41      // determine whether more than eight students passed
42      if ( passes > 8 )
43         cout << "Raise tuition " << endl;
44  } // end function processExamResults

               

Lines 16–18 of Fig. 4.13 declare the variables that member function processExamResults of class Analysis uses to process the examination results. Note that we have taken advantage of a feature of C++ that allows variable initialization to be incorporated into declarations (passes is initialized to 0, failures is initialized to 0 and studentCounter is initialized to 1). Looping programs may require initialization at the beginning of each repetition; such reinitialization normally would be performed by assignment statements rather than in declarations or by moving the declarations inside the loop bodies.

The while statement (lines 22–36) loops 10 times. During each iteration, the loop inputs and processes one exam result. Notice that the if...else statement (lines 29–32) for processing each result is nested in the while statement. If the result is 1, the if...else statement increments passes; otherwise, it assumes the result is 2 and increments failures. Line 35 increments studentCounter before the loop condition is tested again in line 22. After 10 values have been input, the loop terminates and line 39 displays the number of passes and the number of failures. The if statement in lines 42–43 determines whether more than eight students passed the exam and, if so, outputs the message "Raise Tuition".

Demonstrating Class Analysis

Figure 4.14 creates an Analysis object (line 7) and invokes the object's processExamResults member function (line 8) to process a set of exam results entered by the user. Figure 4.14 shows the input and output from two sample executions of the program. At the end of the first sample execution, the condition in line 42 of member function processExamResults in Fig. 4.13 is true—more than eight students passed the exam, so the program outputs a message indicating that the tuition should be raised.

Fig. 4.14 Test program for class Analysis.

 1  // Fig. 4.14: fig04_14.cpp
 2  // Test program for class Analysis.
 3  #include "Analysis.h" // include definition of class Analysis
 4
 5  int main()
 6  {
 7     Analysis application; // create Analysis object                      
 8     application.processExamResults(); // call function to process results
 9     return 0; // indicate successful termination
10  } // end main

               
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 2
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 1
Passed 9
Failed 1
Raise tuition
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 2
Enter result (1 = pass, 2 = fail): 2
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 2
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 1
Enter result (1 = pass, 2 = fail): 2
Passed 6
Failed 4

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020