Consider this C code to swap two integers and these five statements after it:
void swap(int *px, int *py)
{
*px = *px - *py;
*py = *px + *py;
*px = *py - *px;
}
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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.
(A) S1
(B) S2 and S3
(C) S2 and S4
(D) S2 and S5
Answer: (C)
Explanation: S2: May generate segmentation fault if value at pointers px or py is constant or px or py points to a memory location that is invalid
S4: May not work for all inputs as arithmetic overflow can occur