Sample Midterm

These are sample questions that are very similar to the ones I will ask on the midterm.

  1. Which of the following is not a valid C variable name?
    1. hello
    2. chomp_burp
    3. whilex
    4. more-more-more
    5. TrUcKiNg
  2. Evaluate the following expressions, assuming a = 1, b = -3, and c = 0. Treat them independently, so (for example) after evaluating (b), use the above values for (c).
    1. a + b < c
    2. c == !a == c
    3. a = ++b; give the values of both a and b as well
    4. a-- == !b; give the value of a as well
    5. a / b
  3. True or False: If x = -1, then if (x) printf("1"); else printf("2"); prints 2.
  4. Write a recursive function to add the integers from a to b. Please assume that ab.
  5. What are all possible outputs of the following code fragment?
    void f(int a, int b)
    {
        printf("%d %d\n", a, b);
    }
    
    void main(void)
    {
        int i = 5;
        f(i++, i++);
    }
    

  6. Given the definitions
        int numbs[10];
        int *ptr = numbs;
    
    which of the following are equivalent, and why?
    1. numbs[3]
    2. numbs + 3
    3. *(numbs + 3)
    4. *(ptr + 3)
    5. *ptr + 3
  7. Use the following code fragment to answer parts (a), (b), and (c):
    for(x = i = 0; i <= 100; i += 2, x += i);
    
    1. In one short sentence, what does this for loop do?
    2. Is the following while loop equivalent? If not, how does its result differ? (Hint: look at the values of both x and i.)
          x = i = 0;
          while( i++ <= 100)
              x += ++i;
      
    3. Does the following for loop do the same thing? If not, what does it do?
          for(x = i = 0; i <= 100; i++){
              if (!(i % 2))
                  continue;
              x = x + i;
      }
      
  8. What does this function do?
    char *x(char *s, char c)
    {
        char *r = NULL;
    
        do{
            while(*s && *s != c)
                s++;
            if (*s)
                r = s; 
        } while(*s++);
        return(r);
    }
    
  9. The following segment of code is supposed to print the number of times the routine a_again is called. Yet, regardless of the input, it prints 0. Why? How would you fix it?
    void a_again(int acount)
    {
        ++acount;
    }
    
    int main(void)
    {
        int c;
        int counter = 0;
    
        while((c = getchar()) != EOF)
            if (c == 'a' || c == 'A')
                a_again(counter);
    
        printf("%d\n", counter);
        return(0);
    }
    

UC Davis sigil
Matt Bishop
Office: 2209 Watershed Sciences
Phone: +1 (530) 752-8060
Email: mabishop@ucdavis.edu
ECS 36A, Programming and Problem Solving
Version of October 21, 2019 at 6:32PM

You can also obtain a PDF version of this.

Valid HTML 4.01 Transitional Built with BBEdit Built on a Macintosh