ENGG1340 COMP2113 Computer Programming II Programming Technologies Module 7 Solved

ENGG1340 COMP2113 Computer Programming II 

Programming Technologies 
Module 7

Self-Review Exercise 

 

1.     Assume that each of the following statement applies to the same program. 

a)             Write a statement that opens file transaction.dat for input; use an ifstream object called inTransaction. 

b)             Write a statement that opens file balance.dat for input; use an ifstream object called inBalance. 

c)             Write a statement that reads integer accountNumber, floating-point amount from the file transaction.dat; use ifstream object inTransaction. 

d)             Write a statement that reads integer accountNumber, string name, floating-point currentBalance from the file balance.dat; use ifstream object inBalance. 

e)             Write a statement that writes integer accountNumber, string name, updated balance which is a floating-point currentBalance + amount to the file balance.dat; use ifstream object inBalance.  

2.     Suppose that numStudents is an int variable and classCode is a string variable.  What are the values of numStudents and classCode after the following input statements execute: 

             

                        cin numStudents; 

                  getline(cin, classCode); 

 

if the input is: 

a)             80 ENGG1111 

b)             80 

            ENGG1111 

             

 

3.     The following program is supposed to read two numbers from a file named numbers.dat and write the product of the numbers to a file named product.dat.  However, it fails to accomplish the task.  Fix by rewriting the program so that it performs what it is supposed to do.   

 

#include <iostream #include <fstream using namespace std; 

 

int main() 

{ 

      int num1, num2;    ifstream infile; 

 

      outfile.open("product.dat");     infile num1 num2; 

      outfile << "Product = " << num1 * num2 << endl;     return 0; 

} 

 

 

             

 

 

Self-Review Exercise                                                    Module 7                                                                         p. 1/2

 

4.     Consider the following statements: 

      struct movieType 

      { 

            string title;            string genre;             int year;          double rating; 

      }; 

      movieType    movies[100]; 

      movieType    oldMovie; 

 

State if each of the following statements is valid or invalid.  If a statement is invalid, explain why. 

(a)            cout << oldMovie.name; 

(b)           movies.year = 2015; (c)       movies[11] = oldMovie; 

(d)       oldMovie.title = "Titanic"; (e)    if (movies[99].genre == "drama")  

                        movies[99].rating = 3.5; 

 

5.     The following program calculates the summation of first n natural numbers. E.g., 𝑖𝑓 𝑛 = 6, 𝑠𝑢𝑚 =

1 + 2 + 3 + 4 + 5 + 6 = 21. Rewrite the sum() that uses recursion to calculate and return the sum of first n. 

 

#include <iostream using namespace std; 

 

// iterative version int sum(int n) 

{ 

                              int sum = 0; 

                              for (int i = 1; i <= n; ++i) 

                                    sum += i; 

                              return sum; 

}  

int main() 

{ 

                              int n; 

 

      cout << "Enter a positive integer: ";   cin n; 

      cout << "Sum of first " << n << " natural numbers = " << sum(n) << endl;  

 

                              return 0; 

} 

 

 

Self-Review Exercise                                                    Module 7                                                                         p. 2/2