What is 1d and 2d array in java with example

What is 1d and 2d array in java with example

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In Java, an array is a collection of elements that are stored in contiguous memory locations. Arrays are one of the most basic data structures used in programming.

1D Array (Single Dimensional Array)

A 1D array is also known as a single-dimensional array or simply an array. It's a linear collection of values, each identified by an index (or subscript). You can think of it as a list of elements that are stored sequentially in memory.

Here's an example of declaring and initializing a 1D array in Java:

int[] scores = {90, 80, 70, 85, 95};

In this example, scores is an integer array with five elements: {90, 80, 70, 85, 95}. Each element can be accessed using its index (or subscript), starting from 0.

For instance, to access the first element (index 0) of the scores array, you would use scores[0], which returns 90. To access the last element (index 4) of the scores array, you would use scores[4], which returns 95.

2D Array (Two Dimensional Array)

A 2D array is a collection of elements that are stored in a grid-like structure, with each row having the same number of columns. It's often used to represent tables or matrices.

Here's an example of declaring and initializing a 2D array in Java:

int[][] grades = {
{90, 80, 70},
{85, 95, 80},
{70, 75, 65}
};

In this example, grades is an integer array with three rows and three columns. Each element can be accessed using its row index (or subscript) and column index (or subscript), starting from 0.

For instance, to access the top-left element (row 0, column 0) of the grades array, you would use grades[0][0], which returns 90. To access the middle-right element (row 1, column 2) of the grades array, you would use grades[1][2], which returns 80.

Key differences between 1D and 2D arrays:

In conclusion, both 1D and 2D arrays are essential data structures in Java programming. Understanding their differences and how to use them effectively can help you write efficient and effective code.

What is 1d and 2d array in java javatpoint

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In Java, an array is a data structure that stores a collection of values or objects of the same type. Arrays are used to store a group of elements, and each element is accessed by its index or position in the array. There are two main types of arrays in Java: 1D (one-dimensional) arrays and 2D (two-dimensional) arrays.

1D Array (One-Dimensional Array)

A 1D array is an array that stores elements of the same type, one after another, in a linear sequence. Each element in the array is accessed by its index, which starts from 0 and increments by 1 for each subsequent element. For example:

int[] scores = new int[5];
scores[0] = 90;
scores[1] = 80;
scores[2] = 70;
scores[3] = 60;
scores[4] = 50;

In the above example, scores is a 1D array of integers with a length of 5. Each element in the array is accessed by its index, such as scores[0], scores[1], and so on.

2D Array (Two-Dimensional Array)

A 2D array is an array that stores elements of the same type, arranged in rows and columns like a table or matrix. Each element in the array is accessed by its row and column index, which start from 0 for each dimension. For example:

int[][] grades = new int[3][4];
grades[0][0] = 90;
grades[0][1] = 80;
grades[0][2] = 70;
grades[0][3] = 60;
grades[1][0] = 95;
grades[1][1] = 85;
grades[1][2] = 75;
grades[1][3] = 65;
grades[2][0] = 100;
grades[2][1] = 90;
grades[2][2] = 80;
grades[2][3] = 70;

In the above example, grades is a 2D array of integers with a length of 3 rows and 4 columns. Each element in the array is accessed by its row and column index, such as grades[0][0], grades[1][2], and so on.

In conclusion, arrays are an essential data structure in Java that allows you to store and manipulate collections of values or objects. Understanding the differences between 1D and 2D arrays can help you write more effective and efficient code.