ch07 - 多维数组.ppt

Liang, Introduction to Java Programming, Eighth Edition, (c) 2011 Pearson Education, Inc. All rights reserved. 0132130807 Chapter 7 Multidimensional Arrays Motivations Thus far, you have used one-dimensional arrays to model linear collections of elements. You can use a two-dimensional array to represent a matrix or a table. For example, the following table that describes the distances between the cities can be represented using a two-dimensional array. Objectives To give examples of representing data using two-dimensional arrays (§7.1). To declare variables for two-dimensional arrays, create arrays, and access array elements in a two-dimensional array using row and column indexes (§7.2). To program common operations for two-dimensional arrays (displaying arrays, summing all elements, finding min and max elements, and random shuffling) (§7.3). To pass two-dimensional arrays to methods (§7.4). To write a program for grading multiple-choice questions using two-dimensional arrays (§7.5). To solve the closest-pair problem using two-dimensional arrays (§7.6). To check a Sudoku solution using two-dimensional arrays (§7.7). To use multidimensional arrays (§7.8). Declare/Create Two-dimensional Arrays // Declare array ref var dataType[][] refVar; // Create array and assign its reference to variable refVar = new dataType[10][10]; // Combine declaration and creation in one statement dataType[][] refVar = new dataType[10][10]; // Alternative syntax dataType refVar[][] = new dataType[10][10]; Declaring Variables of Two-dimensional Arrays and Creating Two-dimensional Arrays int[][] matrix = new int[10][10]; or int matrix[][] = new int[10][10]; matrix[0][0] = 3; for (int i = 0; i matrix.length; i++) for (int j = 0; j matrix[i].length; j++) matrix[i][j] = (int)(Math.random() * 1000); double[][] x; Two-dimensional Array Illustration Declaring, Creating, and Initializing Using Shorthand Notations You can also use an array initializer to declare, create and initial