Chapter 11 Exercise Set 1: CPE Practice

Bitwise Operators

C++ has the following operators that work at the level of bits:

• Bitwise AND (&)

• Bitwise OR (|)

• Bitwise XOR (^)

• Bitwise NOT (~)

• Left Shift (<<)

• Right Shift (>>)

1. What is the output of the following program?

   #include <iostream>
   using namespace std;
   
   int main() {
       int a[6];
       for (int i = 0; i < 6; i++)
           a[i] = 2 * i + 4;
       cout << a[4] / a[1] << endl;
   
       return 0;
   }
   

   1. 1

   2. 2

   3. 4

   4. 8

2. What is the output of the following program?

   #include <iostream>
   using namespace std;
   
   int main() {
       int a = 2, b = 3;
       if (a > b && b > a)
           a++;
       if (a > b || b > a)
           b++;
       if (a | b)
           a++;
       if (a & b)
           b++;
       cout << a * b << endl;
   
       return 0;
   }
   

   1. 6

   2. 9

   3. 8

   4. 12

3. What is the output of the following program?

   #include <iostream>
   using namespace std;
   
   int main() {
       int a = 1, b = 2, c;
       a = a << b;
       b = b << a;
       c = b >> a;
       cout << c << endl;
   
       return 0;
   }
   

   1. 2

   2. 4

   3. 6

   4. 8

4. What is the output of the following program?

   #include <iostream>
   using namespace std;
   
   int main() {
       float a[3][3] = {{.1, 1., 10.}, {10., .1, 1.}, {.1, 10., 1.}};
       float f = 10.;
       for (int i = 0; i < 3; i++)
           f *= a[i][i];
       cout << f << endl;
   
       return 0;
   }
   

   1. 100

   2. 0.1

   3. 0.01

   4. 10

5. What is the output of the following program?

   #include <iostream>
   using namespace std;
   
   int main() {
     int nums[4] = {16, 8, 4, 2};
     int *p1 = nums + 2, *p2 = p1 - 1;
     p1++;
     cout << *p1 << ' ' << *p2 << ' ' << p1 - p2 << ' ';
     cout << *p1 + nums[p1 - p2] << endl;
   
     return 0;
   }