Which of the following statements is true after the execution of the following statement? y = abs(x)

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Following questions have been asked in GATE CS 2014 exam.
1) Consider the following program in C language: 
 

C

#include <stdio.h>

main()

{

    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: 
 

C

int func(int num)

{

    int count = 0;

    while (num)

    {

        count++;

        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. 
 

C

int f(int j)

{

  static int i = 50;

  int k;

  if (i == j)

  {

    printf("something");

    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. 
 

C

int ProcessArray(int *listA, int x, int n)

{

    int i, j, k;

    i = 0;

    j = n-1;

    do{

        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(k);

    else

        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 
 

C

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 
Explanation: 
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  – 3 ) 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 
GATE-CS-2014-(Set-1) 
GATE-CS-2014-(Set-2) 
GATE-CS-2014-(Set-3)
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