Winter 2005 CS 31 Practice Midterm Answer Key

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       PART I.
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1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18 
d   c   b   b   a   b   c   d   a   c   c   e   d   d   e   c   c   d

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       PART II.
------------------------

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Q19 
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Please refer to the online supplements to lecture.

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Q20 
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A variable is an object with an identifier.  Please see
the online terminology page for the list of attributes.

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Q21
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puzzle(s) displays the ASCII values of the characters
stored in string s.

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Q22 
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riddle(n, b) displays the base-b representation
of the positive integer n, as long as b > 1 and n > 0.  
If b == 1 and n > 0, an infinite recursion results.
If b <= 0 or n <= 0, the function does nothing.

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Q23 
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Please compare to the online GPA example.

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       PART III.
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Question 24.
void drawRectangle (int height, int width, char fill)
{   
   for (int i = 1; i <= height; i++)
   {
      for (int j = 1; j <= width; j++)
         cout << fill;
      cout << endl;
   }
}

Question 25.
void drawRecRow (int height, int width, string fill)
{   
   for (int i = 1; i <= height; i++)
   {
      for (int j = 0; j <= fill.size(); j++)
         for (int k = 1; k <= width; k++)
            cout << fill[j];
      cout << endl;
   }
}

Question 26.
string leftShift (string str)
{   
   if (str.size() == 0)
      return str;
   else
      return    str.substr(1, str.size()-1)
	      + str.substr(0,1);
}

Question 27.
void drawQuilt (int height, int width, string fill)
{
   for (int i = 1; i <= fill.size(); i++)
   {
      drawRecRow(height, width, fill);
      fill = leftShift(fill);
   }
}