JAVA新手一些問題，如何寫出5x5陣列與相關變化

Question

我是一個自學JAVA的新手，想請教高手們一些問題

如何寫出一個同時具有5x5的二維陣列，然後數值不但能隨機由50~100產生，除了不重覆，而且還要計算出每列的平均值與總合？

目前只知道5x5應該是要這樣寫

int [][] a = {{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}};

可是隨機變數跟每一列要求的平均值我不知道要怎麼寫...能否幫幫我解答這個疑問呢？

? · Accepted Answer

請參考我的做法

public class Y12126 {
    public static void main(String[] args) {
        // generate 25 non-duplicate integers
        int[] ary1 = new int[25];
        for (int i = 0; i < ary1.length; i++) {
            while (true) {
                int x = (int)(Math.random() *  51) + 50;
                if (noDuplicate(ary1, x)) {
                    ary1[i] = x;
                    break;
                }
            }
        }
        
        // populate to 5x5 array with sum/average calculation
        int[][] ary2 = new int[5][5];
        int[] sums = new int[5];
        double[] avgs = new double[5];
        for (int i = 0; i < ary2.length; i++) {
            int sum = 0;
            for (int j = 0; j < ary2[i].length; j++) {
                ary2[i][j] = ary1[i*5+j];
                sum += ary2[i][j];
            }
            sums[i] = sum;
            avgs[i] = sum/5.0D;
        }
        
        // Print out
        for (int i = 0; i < ary2.length; i++) {
            System.out.print(java.util.Arrays.toString(ary2[i]));
            System.out.println("&#92;tSum: " + sums[i] + "&#92;tAverage: " + avgs[i]);
        }
    }
    
    public static boolean noDuplicate(int[] ary, int x) {
        for (int i = 0; i < ary.length; i++) {
            if (x == ary[i]) return false;
        }
        return true;
    }
}

黑田憂 · Answer

private int[][] array; //二元陣列
private int size; //陣列大小(size*size)
public Matrix(int value){ //建構子
size=value;
array=new int[size][size];
}
public static void show(Matrix m){ //亂數給值(50~100)
for (int i=0;i<m.size;i++){
for (int j=0;j<m.size;j++){
m.array[i][j]=(int) (Math.random()*51)+50;
System.out.print("A["+i+"]["+j+"]: "+m.array[i][j]+"&#92;t");
}
System.out.println();
}
}
public static void rows(Matrix m){ //每列加總及總合平均值
int[] c=new int[m.size];
for (int i=0;i<m.size;i++){
for (int j=0;j<m.size;j++){
c[i]+=m.array[j][i];
}
System.out.print("R["+i+"]: "+c[i]+"&#92;t");
}
System.out.println();
//列平均
double result=0;
for (int d:c){
result+=d;
}
result=result/m.size;
System.out.println("列平均: "+result);
}
public static void getTransPose(Matrix m1,Matrix m2){ //置換陣列m1->m2
for(int i=0;i<m1.size;i++){
for (int j=0;j<m1.size;j++){
m2.array[i][j]=m1.array[j][i];
System.out.print("T["+i+"]["+j+"]: "+m2.array[i][j]+"&#92;t");
}
System.out.println();
}
}
public static void main(String[] args){ //主程式
Matrix m=new Matrix(5);
Matrix m1=new Matrix(4);
Matrix m2=new Matrix(4);
show(m);
show(m1);
rows(m1);
getTransPose(m1,m2);
rows(m2);
}
}

您參考看看QQ,不過亂數值"可能"會重覆.

2008-04-06 23:56:34 補充：
在下的列平均是全部,若想要每列的得修改一下.

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JAVA新手一些問題，如何寫出5x5陣列與相關變化

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