Java—转置数组

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60

import static java.lang.System.out;
import java.util.Random;

public class Reverse2dArray {   
    static int[][] a; // 存放两位随机整数的int二维数组a      
    
    /**    
    * 构造方法，初始化数组a，r和c分别是行数和列数row column    
    */   
    public Reverse2dArray(int r, int c){       
        a = new int[r][c];   
        buildRandArray();   
    }     
    
    /**    
    * 构造随机数组   
    */   
    public void buildRandArray(){   
        Random random = new Random();     
        for(int i = 0; i < a.length; i++)      
            for(int j = 0; j < a[i].length; j++)         
                a[i][j] = random.nextInt(100); 
    }     
    
    /**    
    * 转置本类成员的二维数组a，并返回一个新的二维数组   
    * @return   
    */   
    public int[][] reverse2dArray(){        
        int [][] b = new int [a[0].length] [a.length] ;
        for (int i = 0; i < a.length; i++) {      
            for (int j = 0; j < a[0].length; j++) {   
                b[j][i] = a[i][j] ;     
            }    
        }     
        return b ; 
    }           
    
    /* 显示二维数组 */  
    public void showArray(int[][] c){    
        out.printf("=========%2d×%-2d=========%n", c.length, c[0].length);       
        for(int[] cr : c){        
            for(int cc : cr){      
                out.printf("%5d ", cc); 
            }         
            out.println();    
        }        
        out.println("=======================");   
    }     
    
    public static void main(String[] args) { 
        int row = 3, col = 4;    
        Reverse2dArray me = new Reverse2dArray(row, col);  
        
        me.showArray(a); // 显示原数组   
        int[][] r = me.reverse2dArray();     
        me.showArray(r); // 显示转置的数组      
    }
}