Arrays
Fixed-size arrays in C++
Interview Relevant: Basic data structure
Arrays
Arrays store fixed-size sequences of elements of the same type.
Key Points
- Fixed size, determined at compile time
- Zero-indexed access
- Contiguous memory allocation
- No bounds checking (undefined behavior if exceeded)
Code Examples
C-style array declaration, initialization, and access.
cpp
1// Declaration and initialization
2int arr[5]; // Uninitialized
3int arr2[5] = {1, 2, 3, 4, 5}; // Initialized
4int arr3[] = {1, 2, 3}; // Size deduced (3)
5int arr4[5] = {1, 2}; // Rest are 0: {1, 2, 0, 0, 0}
6int arr5[5] = {}; // All zeros
7
8// Access elements
9arr2[0] = 10; // First element
10arr2[4] = 50; // Last element
11
12// Array size
13int size = sizeof(arr2) / sizeof(arr2[0]); // 5
14
15// Iterate
16for (int i = 0; i < 5; i++) {
17 cout << arr2[i] << " ";
18}
19
20// Range-based for
21for (int x : arr2) {
22 cout << x << " ";
23}
24
25// Arrays decay to pointers
26int* ptr = arr2; // Points to first element
27cout << *(ptr + 2); // arr2[2]