Data Types — Test 3

Correct Answer: A. 1 and 4
Explanation: len on a str counts code points. The UTF-8 encoding of this emoji uses 4 bytes.

Correct Answer: A. It is variable-length (1 to 4 bytes per character) and backward-compatible with ASCII
Explanation: The '8' in UTF-8 refers to its 8-bit code units, not 8 bytes per character. ASCII characters still take 1 byte.

Correct Answer: B. Both are 3
Explanation: length() and size() are synonyms. Neither counts a terminating null.

Correct Answer: B. 1036
Explanation: base + (i × cols + j) × size = 1000 + (2×4 + 1) × 4 = 1036. ALSO KNOW (related points): • In which order does C/C++ store multidimensional arrays? → Row-major order • How is a Python list implemented in CPython? → As a dynamic array of references, with amortized O(1) append

Correct Answer: A. Row-major order
Explanation: Fortran and MATLAB use column-major order. C and C++ use row-major order.

Correct Answer: C. 8 (the size of a pointer)
Explanation: Array parameters are adjusted to pointers, so the [10] is ignored. ALSO KNOW (related points): • Is int n; cin >> n; int a[n]; standard C++? → No; variable-length arrays are not part of standard C++ (some compilers accept them as an extension) • What is the time complexity of accessing the i-th element of a singly linked list? → O(n)

Correct Answer: D. No; variable-length arrays are not part of standard C++ (some compilers accept them as an extension)
Explanation: VLAs exist in C99, but not in ISO C++. Use std::vector instead.

Correct Answer: C. As a dynamic array of references, with amortized O(1) append
Explanation: This is why indexing is O(1) and inserting at the front is O(n).

Correct Answer: B. O(n)
Explanation: A linked list must be traversed from the head. Arrays support O(1) random access.

Correct Answer: A. p is int*; q is int
Explanation: The * binds to the declarator, not the type, so it applies only to p. Write int *p, *q; for two pointers. ALSO KNOW (related points): • What is the main advantage of nullptr (C++11) over NULL? → It has its own type (std::nullptr_t) and is never mistaken for an integer during overload resolution