One D Arrays

int a[5] = {10, 20, 30, 40, 50}; // Full
int b[5] = {1, 2};              // Partial {1,2,0,0,0}
int c[]  = {1, 2, 3};           // Auto-sized [3]
int d[5] = {0};                 // All zeros

for (int i = 0; i < 5; i++) {
    cout << arr[i] << " ";
}

1D arrays are the foundation for more complex structures like Stacks, Queues, and Hash Tables. They provide O(1) time complexity for random access.