h07: Chapter 6: File IO, Chapter 9: Dynamic memory allocation

Read Chapter 6, Chapter 9, sections 9.1-9.2 (pages 508 - 533). The key learning goals are dynamic memory allocation and its use in dynamic arrays and linked-lists. You don’t need to turn this homework in. To earn credit for this homework, complete the corresponding quiz on gauchospace AFTER you have completed the pen and pencil version of the homework. The quiz will be available one day before the due date indicated on the homework.

PLEASE MARK YOUR HOMEWORK CLEARLY, REGARDLESS OF IF YOU WRITE IT OUT IN INK OR PENCIL! FOR BEST RESULTS, SAVE THIS PAGE AS A PDF, THEN PRINT THE PDF.

1.(10 pts) What is the output of the following program? Using a pointer diagram show the evolution of all data objects in memory, clearly marking elements on the run-time stack and on the heap. Mark the size of all data objects. Assume the code is embedded in a correct and complete program.

int *p1, *p2, *p3;
p1 = new int;
p2 = new int;
p3 = p1;
*p1 = 20;
*p2 = 30;
cout<< *p1<< " "<< *p2<<" "<<*p3<< endl;
p1 = p2;
cout<< *p1<< " "<< *p2<<" "<<*p3<< endl;
*p3 = *p2;
cout<< *p1<< " "<< *p2<<" "<<*p3<< endl;

2.(10 pts) What is the output of the following program? Using a pointer diagram show the evolution of all data objects in memory, clearly marking elements on the run-time stack and on the heap. Mark the size of all data objects. Assume the code is embedded in a correct and complete program.

int array_size = 4, *a ;
a = new int[array_size];
int *p = a;
for(int i=0; i< array_size; i++)
    *(a+i) = 2*i;
p[0] = 10;
for(int i=0; i< array_size; i++)
    cout<<a[i]<<" ";
cout<<endl;

3.(10 pts) Write the definition of a structure type called UndergradStudents. This structure should contain student ID numbers, first and last names, major, and GPA scores for each undergraduate year.

4.(20 pts) Write a program that uses the definition of the structure UndergradStudents from the previous question to declare and then initialize an array of 3 objects of this structure (hint: you can do this with the same approach you define/initialize an array of any other type). You must initialize the values in the program, not by user input. The initial values are shown in the table below. Then write the definition of a function with the signature void printRecords(UndergradStudents *records, int numrecords); The function should print out the values of the array of objects passed to it as shown in the sample below, along with each student’s AVERAGE GPA score (calculated to a precision of 2 decimal places). You must use a loop to print the output. Your program should appropriately call the printRecords() function to print the student records and the average GPA.

These are the student records:
ID# 1, Shmoe, Joe, Major: EE, Average GPA: 3.60
ID# 2, Chen, Macy, Major: CS, Average GPA: 3.95
ID# 3, Peter, Patrick, Major: ME, Average GPA: 2.77

1  #include <iostream>
2  using namespace std;
4  int main() {
5     char first, second;
6     cout << "Enter a word: ";
7     first = cin.get();
8     cin.sync();
9     second = cin.get();
10    cout << first << endl;
11    cout << second << endl;
12    return 0;
13  }

(a) First

(b) Second

(c) Return first 2 letter of number from the entered word

(a) Binary

(b) Text
 
(c) Can't say

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

      int main ()
      {
         string data;
         _____________ outfile;
         outfile.open("file.dat");
         cout << "Writing to the file" << endl;
         cout << "Enter class name: ";
         ___________________________________________
         outfile << data<< endl;
         cout << "Enter your id: ";
         cin >> data;
         cin.ignore();
         outfile << data<< endl;
         outfile.close();
         ifstream infile;
         cout << "Reading from the file" << endl;
         infile.open("file.dat");
         ___________________________________________
         cout << data << endl;
         ___________________________________________
         cout << data << endl;
         infile.close();
         return 0;
      }

    Writing to the file
    Enter class name: name
    Enter your id: 123
    Reading from the file
    name
    123