Arrays Questions and Answers

Answer: D

Correct answer: Theoretically no limit. The only practical limits are memory size and compilers

The standard fixes no maximum number of dimensions; it only requires an implementation to support a certain depth of declarator nesting. So the limit is practical - how much memory the array would need, and how deeply the compiler will nest. Note that memory grows as the product of the bounds, so even four modest dimensions can exhaust it.

Answer: B

Correct answer: the first (row) subscript may be left empty

For a two-dimensional parameter the compiler needs the row length - the number of columns - to compute a[i][j] as *(base + i*cols + j). The number of rows is never used in that arithmetic, so void f(int a[][10]) is legal while void f(int a[10][]) is not. Leaving the first subscript out is optional, not required.

Answer: D

Correct answer: Output : 23

gcvt(value, ndigit, buf) converts a double to a string with ndigit significant digits - not decimal places. With ndigit = 2, 23.45 rounds to two significant figures, giving 23, which is what is printed.

Answer: D

Correct answer: All of the above

All three reasons hold. Storage is proportional to the actual data rather than to the longest name times the count, since each string occupies only what it needs. Swapping exchanges two pointers instead of copying whole rows of characters. And because the swaps are so much cheaper, the sort runs faster.

Answer: D

Whenever a particular memory location is referred, it is likely that the locations nearby are also referred, arrays are stored as contigous blocks in memory, so if you want to access array elements, spatial locality makes it to access quickly.

Answer: B

Correct answer: No

There is no difference. In a parameter list an array declarator is adjusted to a pointer, so both int arr[] and int arr[2] become int *arr. The compiler ignores the bound entirely - which is why a function cannot tell how long the array it was passed really is, and why the length is usually passed as a second parameter.

Answer: D

Correct answer: compiler dependent

The C standard sets no fixed maximum. It specifies only a minimum that a conforming implementation must support - historically 12 levels of array, pointer and function declarators - so the practical ceiling is whatever the compiler allows. In practice arrays of more than three or four dimensions are rare.

Answer: D

Correct answer: 60

The size of an array is the number of elements times the size of one element:

So sizeof(arr) gives 60. Note that this holds only where the array itself is in scope - passed to a function it decays to a pointer, and sizeof then yields the pointer’s size.

Answer: A

Correct answer: An array of 50 numbers

Only scores above 50 are to be reported, and the scores run from 0 to 100. That leaves the 50 values 51, 52, …, 100, so an array of 50 counters is enough - score \(s\) increments the cell at index \(s - 51\). Arrays of 100, 500 or 550 would work but waste space; the question asks for the best choice.

Answer: C

Correct answer: Array of Integer Pointers of size 20

Subscript binds more tightly than the dereference, so int *ptr[20] groups as int *(ptr[20]): an array of 20 pointers to int. A pointer to an array of 20 ints would need parentheses in the other place - int (*ptr)[20].