ex3(2).java

JAVA编程思想第四版英文原版习题答案. pdf原版的

// arrays/Ex3.java
// TIJ4 Chapter Arrays, Exercise 3, page 758
/* Write a method that creates and initializes a two-dimensional array of double. 
* The size of the array is determined by the * arguments of the method, and the 
* initialization values are a range determined by beginning and ending values 
* that are also arguments of the method. Create a second method that will print 
* the array generated by the first method. In main() test the methods by 
* creating and printing several different sizes of arrays.
*/
import java.util.*;

public class Ex3 {
	static double[][] createArray(int size1, int size2, 
	double start, double end) {
		if(!(start < end)) {
			System.out.println("Start must be less than end");
			return null;
		}
		if((size1 < 1) || (size2 < 1)) {
			System.out.println("Size must be > 0");
			return null;
		}
		double[][] result = new double[size1][size2];
		result[0] = new double[size2];
		for(int j = 0; j < size2; j++)
			result[0][j] = (start + ((double)j/(size2 - 1)) * (end - start));
		if(size1 == 1) 	return result;
		else 
		for(int i = 1; i < size1; i++) {
			result[i] = new double[size2];
			for(int j = 0; j < size2; j++) {
				result[i][j] = start + 
				((double)j/(size2 - 1))*(((double)j + (double)i)/(size2 - 1 + i)) * 
				(end - start);
			}
		}
		return result;
	} 
	static void printArray(double[][] da) {
		System.out.println(Arrays.deepToString(da));
	}
	public static void main(String[] args) {
		printArray(createArray(0,2,4,5));
		printArray(createArray(2,3,5,4));
		printArray(createArray(1,2,5,10));
		printArray(createArray(2,2,5,10));
		printArray(createArray(3,3,5,10));
		printArray(createArray(3,5,10,20));
	}
}