C++ · Chapter 21 of 49
C++ Multidimensional Arrays
A 2D array is declared as `type name[rows][cols]` and can be visualised as a grid or table. It's stored as one contiguous block of memory in row-major order.
Nested loops are the standard way to fill and traverse multidimensional arrays, using one loop variable per dimension.
Declaring a 2D array
`int grid[2][3] = {{1,2,3},{4,5,6}};` creates a 2-row, 3-column array. Access an element with `grid[row][col]`.
Traversing with nested loops
An outer loop typically walks rows while an inner loop walks columns, printing or summing every element in the grid.
Example 1 (cpp)
int grid[2][2] = {{1,2},{3,4}};
std::cout << grid[1][0];Output
3grid[1][0] accesses row 1, column 0.
Example 2 (cpp)
int grid[2][2] = {{1,2},{3,4}};
for (int i=0;i<2;i++)
for (int j=0;j<2;j++)
std::cout << grid[i][j];Output
1234Nested loops visit every cell in row-major order.
Key points
- 2D arrays are declared as type name[rows][cols].
- Access elements with arr[row][col].
- Stored contiguously in row-major order.
- Nested loops are used to fill/traverse them.
💡 Note: For dynamic sizes, prefer std::vector<std::vector<int>> over raw 2D arrays.