06 Arrays Free Online FlashCards

What is a C++ built-in array?

A built-in array is a fixed-size sequence of elements of one type stored in contiguous memory.

What should a range-based loop use to modify array elements?

Use a reference, such as `for (int& value : values)`, when the loop must modify the original elements.

What indices are valid for an array with $N$ elements?

For an array with $N$ elements, valid indices run from $0$ through $N-1$.

What is the general syntax for declaring a one-dimensional array?

The declaration syntax is `type name[size];`. The size specifies how many elements the array contains.

What happens when an initializer has too few values?

The remaining elements are value-initialized; for an integer array, they become $0$.

How can C++ deduce a built-in array's size?

The compiler deduces the bound from the number of supplied initializers, so `int primes[] = {2, 3, 5, 7, 11};` creates five elements.

Why does `char word[] = "hello";` contain six characters?

The terminating null character `\0` is included, so `char word[] = "hello";` contains six characters.

What happens when a built-in array is accessed out of bounds?

Accessing an index outside $0$ through $size-1$ produces undefined behavior; C++ does not automatically check built-in array bounds.

How can code compute a local built-in array's element count?

For an array in its original scope, `sizeof(values) / sizeof(values[0])` computes its element count.

Why cast the sum when computing an array average?

Cast the sum to `double` before division, as in `static_cast<double>(sum) / count`, to avoid integer division.

How are indices interpreted in `int matrix[2][3]`?

In `int matrix[2][3]`, the first index selects one of two rows and the second selects one of three columns.

Which index varies fastest during multidimensional initialization?

The rightmost index varies fastest: initialization proceeds through `matrix[0][0]`, `matrix[0][1]`, `matrix[0][2]`, then the second row.