ExamNotice

/*Objective Questions: 30 questions*/

Time duration: 30 minutes.

1. What is the output of the following operation?
0x7e00e9 % 0x7

2. What does a sticky bit do and why?

3.

/* Question is how many processes are created when this program is run */

int main()
{
forkthem(5);
}

void forkthem(int n)
{
if (n>0)
{
fork();
forkthem(n-1);
}
else return;
}

4. preorder and inorder was given, asked which of the options was postorder

/* Please complete */

5. Which of the following representations do not need braces or parenthesis
- prefix, postfix & infix;

6. Give the grammar - E -> E*E | E+E | n,
is it ambiguous? left recursive? none?

7. given the following code in two threads, what will be the range of possible values of n?

/* First Thread */
sum = 0;
for(i = 1;i<5;i++)
{
sum++;
}

/*Secdond thread */
sum = 0;
for(j=1;j<5;j++)
{
sum++;
}

8. The regex in bourne shell to find all files except those starting with
. and ..

The choices involved a lot of [!.] based regexes.

9. One question on
- true hits & true misses
- conflict misses
- cache line ping pong
on a SMP 2 processor machine.

10. You are logged in on a system. Somebody mounts a file system on /home.
a) Would you remain logged in?
b) You logout and you login back again. Would you be able to do that?

11. Some question on sorting algorithms (?)
which of the following algorithms is least dependent on the original ordering of the numbers:
Bubble, insertion, merge & quicksort

12. Why recursion not possible in Fortran?
a) No Stack structure
b) No Dynamic Allocation etc etc

13. Some CFG is given and asked to choose the string accepted by this grammar.

14. /* So far thats what we have recollected... */

*********************************************************************

/* Subjective Questions: 3. Each with 2/3 sub parts. */
Time duration: 20 + 5minutes extra.
1. Fill in the blanks:

Part A
------
/* The following program aims to check whether "a" is a power of 2.

int power2(int a)
{
int b;
b = _____;
if ((a^b)>>1 == b) return 1;
else return 0;
}

Part B
------

/*Following is used to find if a 32-bit number is divisible by 3 */

int div3(int n)
{
int i;
int sum = 0;
for(i = 0;i<32;i++)
{
if(i & 1)
sum += n&i;
else
sum -= n&i;
n>>=1;
}

if(sum == 0) return sum;
if(sum <0) sum = -sum; /* changed. */
if(sum <3) return sum;

return ______;
}

2. Following is used for mutual exclusion:

Part A
------

while(1)
{
while(________);
if (!test_and_set(lock)) break;
}

Part B
------

A program is given, and to say what it prints:

char *p = "char *p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}

Part C
------

main()
{
printf("%d",f(8));
}

int f(int i)
{
return ((--i>1)? f(i) - f(i-1):0);
}

3. Find whether the following programs have any compilation errors?

Part A
------
#define SRP1 struct record *
typedef struct record * SRP2;

SRP1 p1, p2;
SRP2 p3, p4;

swap()
{
SRP2 temp1, temp2;
temp1 = p1;
p1 = p3;
p3 = temp1;
temp2 = p2;
p2 = p4;
p4 = temp2;
}

Part B
------
#define EIGHT 08

main()
{
int nine;
char *string="abcdefgh"
nine= EIGHT;
printf("%d",string[nine]);
}