Consider the following C code segment.

int a, b, c = 0;
void prtFun(void);
main( )
{ 
   static int a = 1; /* Line 1 */
   prtFun();
   a + = 1;
   prtFun();
   printf("\n %d %d ", a, b);
}
void prtFun(void)
{ 
   static int a=2;   /* Line 2 */
   int b=1;
   a+ = ++b;
   printf("\n %d %d ", a, b);
}

What output will be generated by the given code segment if:
Line 1 is replaced by auto int a = 1;
Line 2 is replaced by register int a = 2;

What is printed by the following C program?

#include < stdio.h >
int f(int x, int *py, int **ppz)
{
   int y, z;
  **ppz += 1; 
   z  = **ppz;
  *py += 2;
   y = *py;
   x += 3;
   return x + y + z;
}
 
void main()
{
   int c, *b, **a;
   c = 4;
   b = &c;
   a = &b; 
   printf( "%d", f(c,b,a));
   getchar();
}

Consider this C code to swap two integers and these five statements:

void swap(int *px, int *py) 
{ 
    *px = *px - *py; 
    *py = *px + *py; 
    *px = *py - *px; 
}

S1: will generate a compilation error

S2: may generate a segmentation fault at runtime depending on the arguments passed

S3: correctly implements the swap procedure for all input pointers referring to integers stored in memory locations accessible to the process

S4: implements the swap procedure correctly for some but not all valid input pointers

S5: may add or subtract integers and pointers.

Consider the following C program segment:

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

The output of the program is