Our typical exams have two parts. Part 1 contains short questions of the form like the "self-test exercises" that you find in the textbook. A good way to study for this type of problems is to go through the "self-test exercises", and check with the solutions that are also provided. Part 2 requires you to write full-length programs like those you have been doing for your homework assignments. Examples of such problems can be found in the textbook under the heading: "Programming Projects".

Here are three examples of full-length programs involving loops and branches.

1. // A computer game in which the player has 6 chances to guess at
   // a secret number randomly picked between 1 and 6 by the program.
   // Use is made of a predefined function rand().
   // Each call to rand() returns an integer randomly distributed
   // between 0 and 32767 (= 2^15 - 1, a predefined constant RAND_MAX).
   
   #include <iostream>
   using namespace std;
   
   int main ( )
   {
       // Initialize variables
       int solution, // the secret number
           guess, // the number picked by the player
           loop; // the loop control variable
   
       // Generate a number between 1 and 6 randomly
       // Note: the number given by rand( ) % 6 is always between 0 and 5
       solution = rand( ) % 6 + 1;
   
       for ( loop = 1; loop <= 6; loop++)
       {
           // Enter a number from the keyboard
           cout << "Enter a number between 1 and 6: ";
           cin >> guess;
   
           // See if the player picks the correct number
           if (guess == solution)
           {
           // Correct number
               cout << "You've guessed the right number after "
               << loop << " trial(s).\n";
               return 0; // Game is over, quit program immediately
           }
           else
           {
               // Incorrect number
               cout << "The number is not correct. Please try again.\n";
           }
           }// end for loop
   
       cout << "You had 6 trials to guess at a number between 1 and 6,\n"
           << "and you still have not come up with the correct number.\n"
           << "You must be really really stupid!\n";
   
   } // end of main
   
   
   
2. // Program to compute the exponential function of a real value x.
   // Algorithm: uses the series representation of the exponential function:
   // exp(x) = 1 + x + x^2/2! + x^3/3! + ... + x^m/m! + ...
   
   // For given values of x and m, where m(=20) is the last term to be summed,
   // sum the series and compare with the exact result.
   // Display the results for k=1, 2, ..., 20.
   // Let the user input the value of x, and allow the user to re-calculate
   // for any other values of x.
   
   // Version 1: sum up to the mth term with no tolerance checking.
   
   #include <iostream>
   #include <cmath> // needed for the exponential function exp( )
   using namespace std;
   
   int main ( )
   {
       int k, // loop index
       m = 20; // maximum number of loops
       double x, // value of x
       xk, // x to the power k
       sum, // sum of series
       fac, // factorial of k: k!
       expx; // exact value of exp(x)
   
       char key; // character key to see if user wants to continue
   
       //cout.setf(ios::scientific); // use scientific notation
       cout.setf(ios::fixed|ios::showpoint); // fixed point & show decimal point
       cout.precision(6); // show 6 decimal places
   
       do
       {
           sum = 1.0; // reset sum to 1
           xk = 1.0; // reset xk to 1
           fac = 1.0; // reset k! to 1
   
           cout << "Enter the value of x: ";
           cin >> x;
           expx = exp(x); // exact value for exp(x)
   
           for (k = 1; k <= m; k++)
           {
               xk *= x; // compute x^k
               fac *= double(k); // compute k!
               sum += xk / fac; // compute & accumulate x^k / k!
               cout << k << ' ' << sum << ' ' << expx << endl;
           }
   
           cout << "Enter \'Y\' or \'y\' to continue,\n"
               << "or any other key to quit: ";
           cin >> key;
       } while (key == 'Y' || key == 'y');
   
   }// end of main
   
   
3. // Program to compute the exponential function of a real value x.
   // Algorithm: uses the series representation of the exponential function:
   // exp(x) = 1 + x + x^2/2! + x^3/3! + ... + x^m/m! + ...
   
   // For given values of x and m, where m(=20) is the last term to be summed,
   // sum the series and compare with the exact result.
   // Display the results for k=1, 2, ..., 20.
   // Let the user input the value of x, and allow the user to re-calculate
   // for any other values of x.
   // This second version stops summing the series as soon as we reach a term
   // that contributes less than 1 part in a million to the series.
   // Note that fabs(x) is a predefined function (in cmath) that
   // takes the absolute value of a float.
   
   // Version 2: sum up to the mth term or till the error tolerance is met.
   
   #include <iostream>
   #include <cmath> // needed for the exponential function exp( )
   using namespace std;
   
   int main ( )
   {
       int k, // loop index
       m = 20; // maximum number of loops
       double x, // value of x
       xk, // x to the power k
       sum, // sum of series
       dsum, // keep tract of the next contribution to the sum
       fac, // factorial of k: k!
       expx; // exact value of exp(x)
   
       char key; // character key to see if user wants to continue
   
       //cout.setf(ios::scientific); // use scientific notation
       cout.setf(ios::fixed|ios::showpoint); // fixed point & show decimal point
       cout.precision(6); // show 6 decimal places
   
       do
       {
           sum = 1.0; // reset sum to 1
           dsum = 1.0; // reset dsum to 1
           xk = 1.0; // reset xk to 1
           fac = 1.0; // reset k! to 1
   
           cout << "Enter the value of x: ";
           cin >> x;
           expx = exp(x); // exact value for exp(x)
   
           for (k = 1; k <= m && fabs(dsum) > 1e-6; k++)
           {
               xk *= x; // compute x^k
               fac *= double(k); // compute k!
               dsum = xk / fac; // next contribution to the sum
               sum += dsum; // compute & accumulate x^k / k!
               cout << k << ' ' << sum << ' ' << expx << endl;
           }
   
           cout << "Enter \'Y\' or \'y\' to continue,\n"
               << "or any other key to quit: ";
           cin >> key;
       } while (key == 'Y' || key == 'y');
   
   }// end of main
   
   
4. // Program to compute the exponential function of a real value x.
   // Algorithm: uses the series representation of the exponential function:
   // exp(x) = 1 + x + x^2/2! + x^3/3! + ... + x^m/m! + ...
   
   // For given values of x and m, where m(=20) is the last term to be summed,
   // sum the series and compare with the exact result.
   // Display the results for k=1, 2, ..., 20.
   // Let the user input the value of x, and allow the user to re-calculate
   // for any other values of x.
   // This second version stops summing the series as soon as we reach a term
   // that contributes less than 1 part in a million to the series.
   // Note that fabs(x) is a predefined function (in cmath) that
   // takes the absolute value of a float.
   
   // Version 3: much more efficient handling of the basic loop.
   
   #include <iostream>
   #include <cmath> // needed for the exponential function exp( )
   using namespace std;
   
   const double TOLERANCE(1e-6);     // sum is stopped when magnitude of new term < TOLERANCE
   
   int main ( )
   {
       int k, // loop index
       m = 20; // maximum number of loops
       double x, // value of x
       sum, // sum of series
       dsum, // keep tract of the next contribution to the sum
       expx; // exact value of exp(x)
   
       char key; // character key to see if user wants to continue
   
       //cout.setf(ios::scientific); // use scientific notation
       cout.setf(ios::fixed|ios::showpoint); // fixed point & show decimal point
       cout.precision(6); // show 6 decimal places
   
       do
       {
           sum = 1.0; // reset sum to 1
           dsum = 1.0; // reset dsum to 1
   
           cout << "Enter the value of x: ";
           cin >> x;
           expx = exp(x); // exact value for exp(x)
   
           for (k = 1; k <= m && fabs(dsum) > TOLERANCE; k++)
           {
               dsum *= x / k; // next contribution to the sum
               sum += dsum; // compute & accumulate x^k / k!
               cout << k << ' ' << sum << ' ' << expx << endl;
           }
   
           cout << "Enter \'Y\' or \'y\' to continue,\n"
               << "or any other key to quit: ";
           cin >> key;
       } while (key == 'Y' || key == 'y');
   
   }// end of main