CS 1005, C Term 2000
Introduction to Programming
Practice Problems for Test 1

  1. a) Circle all syntactically correct C++ statements among the following. 
       int k;

   bool IsEven(int n);

   k-;  

   if (k==1) {
      k += 1;
   }

    b) State two advantages of using functions in program design.

  2. Using the function IsPrime whose specification is given here: 
       bool IsPrime(int n)
   // Returns true if n>1 and the only divisors of n are 1 and n
   // Returns false otherwise
   (function body not shown)
    fill in the main() function below so that it prints all prime numbers between 1 and 10,000 to the console output cout. A prime number is an integer p for which the function invocation IsPrime(n) returns true. Consecutive numbers should be separated by spaces in the output.

  3. For each of the following program segments, state what output is produced. 
    a) int i=12;
   cout << i%5;     

b) int j=9;
   cout << ++j;     

c) int k=1;
   while (k/4 < 2) 
      k*=3;
   cout << k;       
 
d) bool flag=false;
   for (int i=1; i<=1000; i++)
      if (i%3 == 0)
         flag = !flag;
   if (flag)
      cout << "true";     
   else if (!flag)
      cout << "false";     

e) int lambda = 32;
   while (lambda > 0) {
      int k=lambda;
      while (k > 0) {
         cout << "*";
         k /= 2;
      }
      cout << endl;
      lambda /= 3;         
   }

  4. Circle all incorrect statements in the following C++ program. In each case, give a brief explanation of what errors are associated with the statement. You may assume that the entirety of the program source file is shown below. 
       int main() {
      double x      
      x = 3;
      y = 4.5;      
      cout << the value of x+y equals << x+y;
      return 0.0;   
   }

  5. Examine the function named UFO defined below and state in words what numbers n yield a return value of true when UFO is called with n as its input argument. 
       bool UFO(int n)
   {
      while (n%2 == 0)
         n/=2;
      return (n==1);
   }