Find the error in each of the following program segments. Assume the following declara- tions and statements:

Question

```
int *zPtr; // zPtr will reference array z
void *sPtr = 0;
int number;
int z[ 5 ] = { 1, 2, 3, 4, 5 };
```

a) ++zPtr;
b) // use pointer to get first value of array
number = zPtr;
c) // assign array element 2 (the value 3) to number
number = *zPtr[ 2 ];
d) // print entire array z
for ( int i = 0; i <= 5; i++ )
cout << zPtr[ i ] << endl;
e) // assign the value pointed to by sPtr to number
number = *sPtr;
f) ++z;

Answer 1

a) ++zPtr;
ANS: Error: zPtr has not been initialized.
Correction: Initialize zPtr with zPtr = z;
b) // use pointer to get first value of array
number = zPtr;
ANS: Error: The pointer is not dereferenced.
Correction: Change the statement to number = *zPtr;
c) // assign array element 2 (the value 3) to number
number = *zPtr[ 2 ];
ANS: Error: zPtr[ 2 ] is not a pointer and should not be dereferenced.
Correction: Change *zPtr[ 2 ] to zPtr[ 2 ].
d) // print entire array z
for ( int i = 0; i <= 5; i++ )
cout << zPtr[ i ] << endl;
ANS: Error: Referring to an array element outside the array bounds with pointer subscripting. Correction: To prevent this, change the relational operator in the for statement to <.
e) // assign the value pointed to by sPtr to number
number = *sPtr;
ANS: Error: Dereferencing a void pointer.
Correction: To dereference the void pointer, it must first be cast to an integer pointer. Change the statement to number = *static_cast< int * >( sPtr );
f) ++z;
ANS: Error: Trying to modify an array name with pointer arithmetic.
Correction: Use a pointer variable instead of the array name to accomplish pointer arithmetic, or subscript the array name to refer to a specific element.