CSCI 3300
Spring 2009
Exercises for Quiz 5

1. We discussed the distinction between two areas of memory: the heap and the run-time stack. Suppose that variable p has type int*. Which of the following is a correct C++ statement or statement sequence that makes p point to newly allocated memory in the heap?

   1. *p = new int;
   2. p = new int;
   3. p = new int*;
   4. int x; p = &x;
   5. int x; *p = x;

   Answer

2. Suppose that p is defined to point to memory as in the preceding question. Which of the following stores 25 in the integer variable to which p points.

   1. p = 25;
   2. p* = 25;
   3. *p = 25;
   4. p = *25;
   5. p *= 25

   Answer

3. What is the value of variable x after performing the following sequence of statements?

     int x = 50;
     int* p = &x;
     *p = 4;
   

   Answer

4. What is the value of variable x after performing the following sequence of statements?

     int y = 7;
     int x = 35;
     int* p = &x;
     p = &y;
   

   Answer

5. What does jump( ) return, where jump is writtten below, using function jumpHelper?

    void jumpHelper(int x)
    {
      x = x + 1;
    }
   
    void jump()
    {
      int z = 40;
      jumpHelper(z);
      return z;
    }
   

   Answer

6. What does hop( ) return, where hop is writtten below, using function hopHelper?

    void hopHelper(int& x)
    {
      x = x + 1;
    }
   
    void hop()
    {
      int z = 40;
      hopHelper(z);
      return z;
    }
   

   Answer

7. What does romp( ) return, where romp is written below, using function rompHelper?

    void rompHelper(int a, int& b)
    {
      b = a + 2;
      a = b + 1;
    }
    int romp()
    {
      int x = 4;
      int y = 25;
      rompHelper(x,y);
      return x + y;
    }
   

   Answer

8. Which of the following will create an array of 30 integers called Orange in the run-time stack?

   1. int[30] Orange;
   2. int* Orange[30];
   3. int Orange[30];
   4. int[] Orange[30];

   Answer

9. Which of the following will create an array of 30 integers called Orange in the heap?

   1. int Orange[30];
   2. int* Orange = new int[30];
   3. int[] Orange = new int[30];
   4. new int[30] Orange;
   5. new int Orange[30];

   Answer

10. Suppose that a C++ program contains the following statements.

      int* p;
      p[0] = 1;
    

    Which of the following is a true statement about what happens?
    1. Performing those statements can cause unpredictable results
    2. The program containing those statements will get a fatal compile error.
    3. Performing those statements will always lead to a run-time error
    4. There is nothing wrong with those statements; they store 1 into the first cell in an array of integers.

    Answer