GATE Questions on C language

12:06 PM 5 Comments

1->
The C language is.
a) A context free language
b) A context sensitive language
c) A regular language
d) Parsable fully only by a Turing machine



2->
The value of j at the end of the execution of the following C program.

int incr (int i)
{
   static int count = 0;
   count = count + i;
   return (count);
}
main ()
{
   int i,j;
   for (i = 0; i <=4; i++)
      j = incr(i);
}

(a) 10
(b) 4
(c) 6
(d) 7



3->
Consider the following C declaration

struct {
    short s [5]
    union {
         float y;
         long z;
    }u;
} t;

Assume that objects of the type short, float and long occupy 2 bytes, 4 bytes and 8 bytes,
respectively.
The memory requirement for variable t, ignoring alignment
considerations, is
(a) 22 bytes
(b) 14 bytes
(c) 18 bytes
(d) 10 bytes



4->
The number of tokens in the following C statement.

 printf("i = %d, &i = %x", i, &i);

is
(a) 3
(b) 26
(c) 10
(d) 21



5->
The following C declarations

struct node
{
   int i;
   float j;
};
struct node *s[10] ;

define s to be

(a) An array, each element of which is a pointer to a structure of type node
(b) A structure of 2 fields, each field being a pointer to an array of 10 elements
(c) A structure of 3 fields: an integer, a float, and an array of 10 elements
(d) An array, each element of which is a structure of type node.




6->
Consider the following C program segment:

char p[20];
char *s = "string";
int length = strlen(s);
int i;
for (i = 0; i < length; i++)
     p[i] = s[length — i];
printf("%s",p);

The output of the program is
a) gnirts
b) gnirt
c) string
d) no output is printed



7->
Consider the following C function

void swap (int a, int b)
{
   int temp;
   temp = a;
   a = b;
   b = temp;
}

In order to exchange the values of two variables x and y.
a) call swap (x, y)
b) call swap (&x, &y)
c) swap (x,y) cannot be used as it does not return any value
d) swap (x,y) cannot be used as the parameters are passed by value



8->
Consider the following C function:

int f(int n)
{
   static int i = 1;
   if (n >= 5)
      return n;
   n = n+i;
   i++;
   return f(n);
}

The value returned by f(1) is
a) 5
b) 6
c) 7
d) 8



9->
Consider the following program fragment for reversing the digits in
a given integer to obtain a new integer.
 Let n = D1D2…Dm

int n, rev;
rev = 0;
while (n > 0)
{
   rev = rev*10 + n%10;
   n = n/10;
}

The loop invariant condition at the end of the ith iteration is:

a) n = D1D2….Dm-i and rev = DmDm-1…Dm-i+1
b) n = Dm-i+1…Dm-1Dm and rev = Dm-1….D2D1
c) n \not = rev
d) n = D1D2….Dm and rev = DmDm-1…D2D1



10->
Consider the following C program

main()
{
   int x, y, m, n;
   scanf ("%d %d", &x, &y);
   /* x > 0 and y > 0 */
   m = x; n = y;
   while (m != n)
   {
      if(m>n)
         m = m - n;
      else
         n = n - m;
   }
   printf("%d", n);
}

The program computes
a) x + y using repeated subtraction
b) x mod y using repeated subtraction
c) the greatest common divisor of x and y
d) the least common multiple of x and y



11->
Assume the following C variable declaration

 int *A [10], B[10][10]; 

Of the following expressions
I A[2]
II A[2][3]
III B[1]
IV B[2][3]
which will not give compile-time errors if used as left hand sides of
assignment statements in a C program

a) I, II, and IV only
b) II, III, and IV only
c) II and IV only
d) IV only



12->
Consider the following declaration of a ‘two-dimensional array in C:

 char a[100][100];

Assuming that the main memory is byte-addressable and that the array is
stored starting from memory address 0, the address of a[40][50] is
a) 4040
b) 4050
c) 5040
d) 5050



13->
Consider the following three C functions :

[FI] int * g (void)
{
  int x = 10;
  return (&x);
}

[F2] int * g (void)
{
  int * px;
  *px = 10;
  return px;
}

[F3] int *g (void)
{
  int *px;
  px = (int *) malloc (sizeof(int));
  *px = 10;
  return px;
}

Which of the above three functions are likely to cause problems with pointers?
(a) Only F3
(b) Only F1 and F3
(c) Only F1 and F2
(d) F1, F2 and F3



14->
The most appropriate matching for the following pairs

X: m=malloc(5); m= NULL;        1: using dangling pointers
Y: free(n); n->value=5;         2: using uninitialized pointers
Z: char *p; *p = ’a’;           3. lost memory is:


(a) X—1 Y—3 Z-2
(b) X—2 Y—1 Z-3
(C) X—3 Y—2 Z-1
(d) X—3 Y—1 Z-2



15->
Consider the following C-program:

void foo(int n, int sum)
{
  int k = 0, j = 0;
  if (n == 0) return;
    k = n % 10;
  j = n / 10;
  sum = sum + k;
  foo (j, sum);
  printf ("%d,", k);
}

int main ()
{
  int a = 2048, sum = 0;
  foo (a, sum);
  printf ("%d\n", sum);
 
  getchar();
}

What does the above program print?
(a) 8, 4, 0, 2, 14
(b) 8, 4, 0, 2, 0
(C) 2, 0, 4, 8, 14
(d) 2, 0, 4, 8, 0


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