Skip to main content

Two-Dimensional Arrays

Two-dimensional arrays are like parking garages with multiple floors—rows and columns. Let’s dive into this multi-level structure.

Declaration and Initialization​

Pseudo-Code:​

DECLARE Grid : ARRAY[1:3, 1:3] OF INTEGER
Grid[1, 1] ← 1
Grid[1, 2] ← 2
Grid[1, 3] ← 3
Grid[2, 1] ← 4
Grid[2, 2] ← 5
Grid[2, 3] ← 6
Grid[3, 1] ← 7
Grid[3, 2] ← 8
Grid[3, 3] ← 9

Python:​

Grid = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
]

Accessing Elements​

Pseudo-Code:​

OUTPUT Grid[2, 3]

Python:​

print(Grid[1][2])  # 0-based indexing

Output:

6

"That’s the spot on the second floor, third column—right near the vending machine." 🥤

Nested Loops for Traversal​

Pseudo-Code:​

FOR Row ← 1 TO 3
    FOR Col ← 1 TO 3
        OUTPUT Grid[Row, Col]
    NEXT Col
NEXT Row

Python:​

for Row in range(3):
    for Col in range(3):
        print(Grid[Row][Col])

Output:

1
2
3
4
5
6
7
8
9

"Exploring every nook and cranny of the parking garage!" 🏢🚗

Example: Multiplication Table 🧮​

Pseudo-Code:

DECLARE Table : ARRAY[1:3, 1:3] OF INTEGER
FOR Row ← 1 TO 3
    FOR Col ← 1 TO 3
        Table[Row, Col] ← Row * Col
    NEXT Col
NEXT Row

FOR Row ← 1 TO 3
    FOR Col ← 1 TO 3
        OUTPUT Table[Row, Col]
    NEXT Col
NEXT Row

Python:

Table = [[Row * Col for Col in range(1, 4)] for Row in range(1, 4)]

for Row in Table:
    for Col in Row:
        print(Col, end=" ")
    print()

Output:

1 2 3 
2 4 6 
3 6 9

"Math just got a whole lot easier—and cooler!" 🕶️

Input/Output Handling for 2D Arrays​

Pseudo-Code:

DECLARE Matrix : ARRAY[1:2, 1:2] OF INTEGER
INPUT Matrix[1, 1]
INPUT Matrix[1, 2]
INPUT Matrix[2, 1]
INPUT Matrix[2, 2]

OUTPUT "Matrix values:"
FOR Row ← 1 TO 2
    FOR Col ← 1 TO 2
        OUTPUT Matrix[Row, Col]
    NEXT Col
NEXT Row

Python:

Matrix = [[int(input(f"Enter value for Matrix[{Row+1}][{Col+1}]: ")) for Col in range(2)] for Row in range(2)]

print("Matrix values:")
for Row in Matrix:
    for Col in Row:
        print(Col, end=" ")
    print()

Example Input:

Enter value for Matrix[1][1]: 10
Enter value for Matrix[1][2]: 20
Enter value for Matrix[2][1]: 30
Enter value for Matrix[2][2]: 40

Output:

Matrix values:
10 20 
30 40

"Building a matrix like a pro—Professor X would be proud!" 📚

Arrays are an incredibly versatile tool in programming. Whether it’s a simple row of numbers or a complex grid, they keep your data structured and accessible. Happy coding! 🎉