C Language | Set 10

Following questions have been asked in GATE CS 2014 exam.

1) Consider the following program in C language:

#include <stdio.h>
    int i;
    int *pi = &i;
    scanf("%d", pi);
    printf("%d\n", i+5);

Which one of the following statements is TRUE?
(A) Compilation fails.
(B) Execution results in a run-time error.
(C) On execution, the value printed is 5 more than the address of variable i.
(D) On execution, the value printed is 5 more than the integer value entered.

Answer: (D)
Explanation: There is no problem in the program as pi points to a valid location.
Also, in scanf() we pass address of a variable and pi is an address.

2) Consider the function func shown below:

int func(int num)
    int count = 0;
    while (num)
        num >>= 1;
    return (count);

The value returned by func(435)is __________.

Answer: 9
Explanation: The function mainly returns position of Most significant bit in binary representation of n. The MSD in binary representation of 435 is 9th bit.

3) Consider the C function given below.

int f(int j)
  static int i = 50;
  int k;
  if (i == j)
    k = f(i);
    return 0;
  else return 0;

Which one of the following is TRUE?
(A) The function returns 0 for all values of j.
(B) The function prints the string something for all values of j.
(C) The function returns 0 when j = 50.
(D) The function will exhaust the runtime stack or run into an infinite loop when j = 50

Answer: (D)
Explanation: When j is 50, the function would call itself again and again as neither i nor j is changed inside the recursion.

4) Consider the C function given below. Assume that the array listA contains n (> 0) elements, sorted in ascending order.

int ProcessArray(int *listA, int x, int n)
    int i, j, k;
    i = 0;
    j = n-1;
        k = (i+j)/2;
        if (x <= listA[k])
            j = k-1;
        if (listA[k] <= x)
            i = k+1;
    } while (i <= j);
    if (listA[k] == x)
        return -1;

Which one of the following statements about the function ProcessArray is CORRECT?
(A) It will run into an infinite loop when x is not in listA.
(B) It is an implementation of binary search.
(C) It will always find the maximum element in listA.
(D) It will return -1 even when x is present in listA.

Answer: (B)
Explanation: The program is a simple iterative C implementation of Binary Search.

5) Consider the following function

double f(double x)
   if (abs(x*x - 3) < 0.01) return x;
   else return f(x/2 + 1.5/x);

Give a value q (to 2 decimals) such that f(q) will return q:_____.

Answer: 1.732
The main thing to note is the expression “abs(x*x – 3) < 0.01" inside the if condition. The function would return x when x2 is close to 0 (smaller than 0.01) which means when x is close to square root of 3. Square root of 3 is 1.732.

See following for complete solutions of all GATE CS 2014 papers


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