Section 0101, 0102, 0103 & Honors, Fall 1995

Final Exam A

True or False Questions, 1 point each

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Multiple Choice, 2 points each

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Short Answers, 4 points each

In the following questions, no syntax errors have been put in deliberately. (So, "there is a syntax error" is not the right answer and will receive no credit.) Please mark your final answer clearly. In order to receive partial credit, you must show your work.

1. Nested loops: write down the output of the following program fragment.

      int i, j ;   
      for (i = 1 ; i < 5 ; i++) {   
        for (j = 0 ; j <= 5 ; j++) {  
            if ( (i + j) % 2 == 0 ) {   
               printf("X") ;        
             } else {           
                printf("O") ;   
             }     
         }     
         printf("\n") ;  
      }    
      

   Sample Solution

2. Pointer manipulations: write down the output of the following program.

      #include <stdio.h>  
      
      main() {  
         int a = 1, b = 2, c = 3 ;     
         int *ptr1, *ptr2, *ptr3;      
         
         ptr1 = &a ;     
         ptr2 = &b ;     
         ptr3 = &c ;
              
         *ptr1 = *ptr2 + *ptr3 ;     
         printf("a = %d, b = %d, c = %d\n", a, b, c) ;
               
         *ptr2 = *ptr1 + b ;     
         printf("a = %d, b = %d, c = %d\n", a, b, c) ;
              
         ptr3 = ptr1 ;     
         printf("a = %d, b = %d, c = %d\n", a, b, c) ;
               
         *ptr1 = *ptr2 + *ptr3 ;      
         printf("a = %d, b = %d, c = %d\n", a, b, c) ; 
      }
      

   Sample Solution

3. Parameter passing by reference: write down the output of the following program.

      #include <stdio.h>  
      
      int palermo (int *, int *) ;   
      
      int palermo (int *p, int *q) {     
         int b ;      
         
         b = *p ;     
         *p = *q + 5 ;     
         *q = b + 5 ;     
         printf("palermo: b = %d, *p = %d, *q = %d\n", b, *p, *q) ;
         return(b) ;  
      }   
      
      main() {     
         int a = 1, b = 7, c = 4 ;      
         a = palermo(&b, &c) ;     
         printf("main: a = %d, b = %d, c = %d\n", a, b, c) ;  
      }
      

   Sample Solution

4. The following program contains several global variables. Trace through the program and write down the output of the program. It is important that you write down the output in the order that they would appear when the program is executed.

      #include <stdio.h>   
      
      int bologna(int) ;   
      
      int a = 1, b = 2, c = 3, d = 4, e = 5 ;   
      
      int bologna(int c) {  
         int e ;      
         
         a = c + 1 ;     
         b = c + 2 ;     
         c = c + 3 ;    
         d = c + 4 ;     
         e = c + 5 ;     
         printf("bologna: a=%d, b=%d, c=%d, d=%d, e=%d\n", a, b, c, d, e) ;
         return(e) ;  
      }   
      
      main() {     
         int b = 10, c = 11 ;      
         
         printf("main: a=%d, b=%d, c=%d, d=%d, e=%d\n", a, b, c, d, e) ; 
         c = bologna(a) ;     
         printf("main: a=%d, b=%d, c=%d, d=%d, e=%d\n", a, b, c, d, e) ;  
      } 
      

   Sample Solution

5. Write a short program that takes an integer value (call it n) from the user and prints out a square of numbers starting with 1 in the top left corner, 2 in a ring around the 1, 3 in a ring around the 2's, For example, if the user enters 3 as the input, your program should print out:

      1 2 3  
      2 2 3  
      3 3 3 
      

   If the user enters 5 as the input, your program should print out:

      1 2 3 4 5  
      2 2 3 4 5  
      3 3 3 4 5  
      4 4 4 4 5  
      5 5 5 5 5 
      

   Sample Solution

6. A perfect number is a positive integer which is equal to the sum of its divisors (not counting the number itself). For example, the number 6 is a perfect number because 1, 2 and 3 are the divisors of 6 and 1+2+3 = 6. Similarly, the number 28 is a perfect number because 1+2+4+7+14 = 28.

   Write a function PerfectNumber which takes an integer parameter and returns TRUE if the parameter is a perfect number. If the parameter is not a perfect number, the function returns FALSE.

   Sample Solution

7. Write a function called DoubleLetter which takes a string parameter and returns an integer value. The value returned by the function is the index of the first character that appears consecutively in the string. If no such character is found, then DoubleLetter returns -1. For example, DoubleLetter("abcdefgghi") should return the value 6 and DoubleLetter("Attila the Hun") should return the value 1.

   Sample Solution