#18 Membuat Pola dengan Array 2 Dimensi & Looping | DASAR PEMROGRAMAN JAVA

Summary

In this Java programming tutorial, the presenter guides viewers through the creation of 2D array patterns. The first pattern uses odd and even rows to alternate between `1` and `0`, while the second pattern focuses on filling the first and last rows with `1` and the inner elements with `0`, forming a bordered effect. Viewers are encouraged to experiment with different symbols and patterns. The tutorial also sets the stage for future lessons on Java methods, functions, and procedures, enhancing the flexibility of the code.

Takeaways

• 😀 The video teaches how to create a 2D array in Java with a specific pattern based on user input for the number of rows and columns.
• 😀 The program uses `Scanner` to take user input for the number of rows and columns, followed by initializing a 2D array.
• 😀 For odd-numbered rows, the array is populated with alternating 1s and 0s, starting and ending with 1.
• 😀 For even-numbered rows, the array is populated with alternating 1s and 0s, starting with 0 and ending with 1.
• 😀 A nested `for` loop structure is used to iterate over the rows and columns of the 2D array to populate the values.
• 😀 The program uses conditional statements to check if the current row is even or odd, which determines the pattern of 1s and 0s.
• 😀 After filling the array, the program uses another `for` loop to print the 2D array to the console in a structured manner.
• 😀 The program demonstrates the importance of understanding loops and conditionals in Java for array manipulation.
• 😀 The video encourages viewers to experiment with other patterns, such as using different characters like '*' or '#'.
• 😀 The next video will cover the differences between methods, functions, and procedures in Java, helping viewers advance their Java knowledge.

Q & A

What is the purpose of the 2D array in the program?

The 2D array is used to represent and store a pattern, where each element in the array corresponds to a part of the design (such as a ball pattern). The pattern's values depend on the row and column positions, which are determined by user input.

How does the program differentiate between odd and even rows?

The program checks if the row index is even or odd. If the row index is even, the array's values are filled with 0 in the middle, with 1 at the first and last columns. If the row index is odd, the array values are all set to 1.

What is the role of the `Scanner` class in the code?

The `Scanner` class is used to get input from the user, specifically the number of rows and columns for the 2D array. This allows the user to customize the size of the pattern generated by the program.

Why are there loops for both rows and columns in the program?

The loops are used to iterate over each element in the 2D array. The outer loop handles the rows, and the inner loop handles the columns. This structure is necessary to fill each cell of the array with the appropriate value (either 1 or 0) based on its row and column index.

How does the program handle the first and last rows?

For the first and last rows, the program sets all values to 1. This is done through a condition that checks if the row index is either 0 (the first row) or the last row (index `rows - 1`).

What happens in the program when the number of rows is even?

When the number of rows is even, the program starts each row with a 0 in the first column, places 1 in the first and last columns, and sets the middle columns to 0. This creates a pattern where the array appears surrounded by 1's with zeros in between.

Can the program handle any number of rows and columns?

Yes, the program is designed to handle any number of rows and columns, provided by the user as input. The only limitation is the available system memory, as large arrays may consume significant resources.

What are the key differences between the two patterns explained in the script?

The first pattern alternates between 1's and 0's, based on whether the row index is odd or even. The second pattern fills the first and last columns with 1's, while the inner columns are filled with 0's, with the first and last rows also filled with 1's.

What is the significance of using 'for' loops in this program?

The 'for' loops are crucial for iterating over the 2D array. The outer loop iterates through each row, while the inner loop iterates through each column in that row. This is necessary to fill and display the array according to the specified pattern.

What is the output of the program when 7 rows and 4 columns are entered?

The output will display a 7x4 array with 1's in the first and last columns, and in the first and last rows, with 0's in the middle columns for the even rows, and the entire row filled with 1's for the odd rows.