一些典型的数组处理方法 赋值初始化 寻找最大值 计算平均值 复制数组 颠倒数组中元素的顺序 矩阵相乘 数组的输出

    //用0-100的数据初始化数组
    public static void randomArry(double a[]) {
        Random ran = new Random();
        int n = a.length;
        for(int i = 0;i <n ;i++) {
            a[i] = ran.nextInt(100);
        }
    }
    //初始化的重载
    public static void randomArry(double a[][]) {
        Random ran = new Random();
        int n1 = a.length;
        int n2 = a[0].length;
        for(int i = 0;i<n1;i++) {
            for(int j = 0;j < n2;j++) {
                a[i][j] = ran.nextInt(100);
                
            }
        }
    }

    //找出数组的最大值
    public static double findMax(double a[]) {
        double max = a[0];
        for(int i = 1;i < a.length;i++) {
            if(a[i] >max) max = a[i];
        }
        return max;
    }
    //找最大值方法要创建一个对应的重载方法
    public static double findMax(double a[][]) {
        int n1 = a.length;
        int n2 = a[0].length;
        double max = a[0][0];
        for(int i = 0; i < n1;i++) {
            for(int j = 0; j < n2;j++) {
                if(a[i][j] >max) max = a[i][j];
            }
        }
        return max;
    }

    //计算数组元素的平均值
    public static double figureAverage(double a[]) {
        int n = a.length;
        double sum = 0;
        for(int i = 0; i < n;i++) {
            sum += a[i];
        }
        return sum/n;
    }
    //当然我们算平均值也要算二维数组了看我们的重载方法如下
    public static double figureAverage(double a[][]) {
        int n1 = a.length;
        int n2 = a[0].length;
        double sum = 0;
        for(int i = 0; i < n1;i++) {
            for(int j = 0; j < n2;j++) {
                sum += a[i][j];
            }
        }
        return sum/(n1*n2);
    }

    //复制数组
    public static double[] copyArry(double a[]) {
        int n = a.length;
        double b[] = new double[n];
        for(int i = 0; i < n;i++) {
            b[i] = a[i];
        }
        return b;
    }
    public static double[][] copyArry(double a[][]){
        int n1 = a.length;
        int n2 = a[0].length;
        double[][] b = new double[n1][n2];
        for(int i = 0; i<n1; i++) {
            for(int j = 0; j < n2; j++) {
                b[i][j] = a[i][j];
            }
        }
        return b;
    }

    //颠倒数组元素的顺序
    public static double[] switchElements(double a[]) {
        int n = a.length;
        for(int i = 0; i< n/2;i++) {
            double temp = a[i];
            a[i] = a[n - 1 -i];
            a[n-1-i] = temp;
        }
        return a;
    }
    //颠倒数组顺序的重载方法
    public static double[][] switchElements(double a[][]){
        int n1 = a.length;
        int n2 = a[0].length;
        for(int i =0;i<n1/2;i++) {
            for(int j = 0;j<n2;j++) {
                if(i+j < (n1+n2)/2) {
                    double temp = a[i][j];
                    a[i][j] = a[n1-i-1][n2-j-1];
                    a[n1-i-1][n2-j-1] = temp;
                }
            }
        }
        return a;
    }

    //矩阵相乘
    public static double[] matrixMuiplication(double a[],double b[]) {
        int n = a.length;
        double[] c = new double[n];
        for(int i = 0;i<n;i++) {
            c[i] = a[i]*b[i]; 
        }
        return c;
    }
    //矩阵相乘的重载(方阵)
    public static double[][] matrixMuiplication(double a[][],double b[][]) {
        int n = a.length;
        double c[][] = new double[n][n];
        for(int i = 0;i < n;i++) {
            for(int j = 0; j<n; j++) {
                //计算行i和列j的点乘
                for(int k = 0; k < n; k++) {
                    c[i][j] += a[i][k]*b[k][j];
                }
            }
        }
        return c;
    }

    //输出数组的方法
    public static void printArry(double a[]) {
        int n = a.length;
        for(int i = 0; i<n ;i++) {
            System.out.print(a[i]+"\t");
        }
        System.out.print("\n");
        System.out.print("\n");
    }
    //数组输出的重载方法
    public static void printArry(double a[][]) {
        int n1 = a.length;
        int n2 = a[0].length;
        for(int i = 0; i<n1 ; i++) {
            for(int j= 0;j<n2;j++) {
                System.out.print(a[i][j]);
                System.out.print("\t");
            }
            System.out.print("\n");
        }
        System.out.print("\n");
    }

  1 import java.util.Random;
  2 
  3 public class DianXingShuZhuChuLiDaiMa {
  4     
  5     
  6     public static void main(String[] args) {
  7         // 接下来对我们的数组方法逐一测试
  8         double a[] = new double[8];
  9         double b[] = new double[8];
 10         double b1[][] = new double[8][8];
 11         double b2[][] =new double[8][8];
 12         printArry(a);
 13         printArry(b);
 14         printArry(b1);
 15         printArry(b2);
 16         //使用随机数来作为我们测试的量
 17         randomArry(a);
 18         randomArry(b);
 19         randomArry(b1);
 20         randomArry(b2);
 21         //输出初始化的值
 22         System.out.println("最初的a是");
 23         printArry(a);
 24         System.out.println("最初的b是");
 25         printArry(b);
 26         System.out.println("最初的b1是");
 27         printArry(b1);
 28         System.out.println("最初的b2是");
 29         printArry(b2);
 30         
 31         //找出a的最大值找出b2的最大值
 32         System.out.println("a的最大值是:"+findMax(a));
 33         System.out.println("b2的最大值是:"+findMax(b2));
 34         //接下来计算数组元素的平均值
 35         System.out.println("a的平均值是"+figureAverage(a));
 36         System.out.println("b1的平均值是"+figureAverage(b1));
 37         //复制数组
 38         double d1[] = copyArry(a);
 39         double d2[][] = copyArry(b1);
 40         System.out.println("复制结果是");
 41         printArry(d1);
 42         printArry(d2);
 43         //颠倒数组的元素顺序
 44         System.out.println("颠倒数组的结果是a & b1");
 45         printArry(switchElements(a));
 46         printArry(switchElements(b1));
 47         
 48         //测试矩阵相乘
 49         System.out.println("ab相乘");
 50         printArry(matrixMuiplication(a,b));
 51         System.out.println("b1 b2相乘");
 52         printArry(matrixMuiplication(b1,b2));
 53         
 54         
 55     }
 56     
 57     //用0-100的数据初始化数组
 58     public static void randomArry(double a[]) {
 59         Random ran = new Random();
 60         int n = a.length;
 61         for(int i = 0;i <n ;i++) {
 62             a[i] = ran.nextInt(100);
 63         }
 64     }
 65     //初始化的重载
 66     public static void randomArry(double a[][]) {
 67         Random ran = new Random();
 68         int n1 = a.length;
 69         int n2 = a[0].length;
 70         for(int i = 0;i<n1;i++) {
 71             for(int j = 0;j < n2;j++) {
 72                 a[i][j] = ran.nextInt(100);
 73                 
 74             }
 75         }
 76     }
 77     
 78     //找出数组的最大值
 79     public static double findMax(double a[]) {
 80         double max = a[0];
 81         for(int i = 1;i < a.length;i++) {
 82             if(a[i] >max) max = a[i];
 83         }
 84         return max;
 85     }
 86     //找最大值方法要创建一个对应的重载方法
 87     public static double findMax(double a[][]) {
 88         int n1 = a.length;
 89         int n2 = a[0].length;
 90         double max = a[0][0];
 91         for(int i = 0; i < n1;i++) {
 92             for(int j = 0; j < n2;j++) {
 93                 if(a[i][j] >max) max = a[i][j];
 94             }
 95         }
 96         return max;
 97     }
 98     
 99     //计算数组元素的平均值
100     public static double figureAverage(double a[]) {
101         int n = a.length;
102         double sum = 0;
103         for(int i = 0; i < n;i++) {
104             sum += a[i];
105         }
106         return sum/n;
107     }
108     //当然我们算平均值也要算二维数组了看我们的重载方法如下
109     public static double figureAverage(double a[][]) {
110         int n1 = a.length;
111         int n2 = a[0].length;
112         double sum = 0;
113         for(int i = 0; i < n1;i++) {
114             for(int j = 0; j < n2;j++) {
115                 sum += a[i][j];
116             }
117         }
118         return sum/(n1*n2);
119     }
120     
121     //复制数组
122     public static double[] copyArry(double a[]) {
123         int n = a.length;
124         double b[] = new double[n];
125         for(int i = 0; i < n;i++) {
126             b[i] = a[i];
127         }
128         return b;
129     }
130     public static double[][] copyArry(double a[][]){
131         int n1 = a.length;
132         int n2 = a[0].length;
133         double[][] b = new double[n1][n2];
134         for(int i = 0; i<n1; i++) {
135             for(int j = 0; j < n2; j++) {
136                 b[i][j] = a[i][j];
137             }
138         }
139         return b;
140     }
141     
142     //颠倒数组元素的顺序
143     public static double[] switchElements(double a[]) {
144         int n = a.length;
145         for(int i = 0; i< n/2;i++) {
146             double temp = a[i];
147             a[i] = a[n - 1 -i];
148             a[n-1-i] = temp;
149         }
150         return a;
151     }
152     //颠倒数组顺序的重载方法
153     public static double[][] switchElements(double a[][]){
154         int n1 = a.length;
155         int n2 = a[0].length;
156         for(int i =0;i<n1/2;i++) {
157             for(int j = 0;j<n2;j++) {
158                 if(i+j < (n1+n2)/2) {
159                     double temp = a[i][j];
160                     a[i][j] = a[n1-i-1][n2-j-1];
161                     a[n1-i-1][n2-j-1] = temp;
162                 }
163             }
164         }
165         return a;
166     }
167     
168     //矩阵相乘
169     public static double[] matrixMuiplication(double a[],double b[]) {
170         int n = a.length;
171         double[] c = new double[n];
172         for(int i = 0;i<n;i++) {
173             c[i] = a[i]*b[i]; 
174         }
175         return c;
176     }
177     //矩阵相乘的重载(方阵)
178     public static double[][] matrixMuiplication(double a[][],double b[][]) {
179         int n = a.length;
180         double c[][] = new double[n][n];
181         for(int i = 0;i < n;i++) {
182             for(int j = 0; j<n; j++) {
183                 //计算行i和列j的点乘
184                 for(int k = 0; k < n; k++) {
185                     c[i][j] += a[i][k]*b[k][j];
186                 }
187             }
188         }
189         return c;
190     }
191     //输出数组的方法
192     public static void printArry(double a[]) {
193         int n = a.length;
194         for(int i = 0; i<n ;i++) {
195             System.out.print(a[i]+"\t");
196         }
197         System.out.print("\n");
198         System.out.print("\n");
199     }
200     //数组输出的重载方法
201     public static void printArry(double a[][]) {
202         int n1 = a.length;
203         int n2 = a[0].length;
204         for(int i = 0; i<n1 ; i++) {
205             for(int j= 0;j<n2;j++) {
206                 System.out.print(a[i][j]);
207                 System.out.print("\t");
208             }
209             System.out.print("\n");
210         }
211         System.out.print("\n");
212     }
213 }