GATE 2006

Question

/* function definition to swap the values */
void swap(int *x, int *y) {

   int temp;
   temp = *x;    /* save the value at address x */
   *x = *y;      /* put y into x */
   *y = temp;    /* put temp into y */
 
   return;
}

#include <stdio.h>
 
/* function declaration */
void swap(int *x, int *y);
 
int main () {

   /* local variable definition */
   int a = 100;
   int b = 200;
   int c;
   printf("Before swap, value of a : %d\n", a );
   printf("Before swap, value of b : %d\n", b );
 
   /* calling a function to swap the values.
      * &a indicates pointer to a ie. address of variable a and
      * &b indicates pointer to b ie. address of variable b.
   */
   c=b+5;
   swap(&a, &c);
 
   printf("After swap, value of a : %d\n", a );
   printf("After swap, value of b : %d\n", b );
 
   return 0;
}

/*IF I USE swap(&a,&(b+5)),it gives error but the above program doesn't give error.

Comments

Consider the following code written in a pass-by-reference language like FORTRAN and these statements about the code. 

subroutine swap(ix,iy) 
     it = ix 
L1 : ix = iy 
L2 : iy = it 
    end 
    ia = 3 
    ib = 8 
    call swap (ia, ib+5)
    print *, ia, ib 
    end 

S1: The compiler will generate code to allocate a temporary nameless cell, initialize it to 13, and pass the address of the cell to swap 
S2: On execution the code will generate a runtime error on line L1 
S3: On execution the code will generate a runtime error on line L2 
S4: The program will print 13 and 8 
S5: The program will print 13 and -2 

Exactly the following set of statement(s) is correct: 

1. S1 and S2 
2. S1 and S4 
3. S3 
4. S1 and S5

Comparing this question with mine?