『JAVA』Vector的指向

import java.util.*;

public class VectorDemo {

public static void main(String[] args){

Vector v = new Vector(4);

v.add("Test0");

v.add("Test1");

v.add("Test0");

v.add("Test2");

v.add("Test2");

v.remove("Test0"); //刪除指定內容的元素

v.remove(0); //按照索引號刪除元素

//獲得Vector中已有元素的個數

int size = v.size();

System.out.println("size:" + size);

//遍歷Vector中的元素

for(int i = 0;i < v.size();i++)

System.out.println(v.get(i));

}

}

當使用v.add(Object)時

其作用方式類似指標

假設我有一個class svm_node{

int index;

double value;

}

多個node欲放入vector中

必須用不同的node作為代表，不可更改同一個node放進去

會全部指向最後一個node

即"Vector"堆疊的是每個Object的記憶體位置

而不是複製一份堆疊進去

Vector vx = new Vector();

svm_node[] x = new svm_node[3];    
x[0] = new svm_node();
x[0].index = color_r;       
x[0].value = 15.0;        
x[1] = new svm_node();
x[1].index = color_g;
x[1].value = 163.0;
x[2] = new svm_node();
x[2].index = color_b;     
x[2].value = 15.0;
vx.add(x);       //儲存SVM node的陣列svm_node[] y = new svm_node[3];
y[0] = new svm_node();
y[0].index = color_r;       
y[0].value = 255.0;            
y[1] = new svm_node();
y[1].index = color_g;      
y[1].value = 42.0;
y[2] = new svm_node();
y[2].index = color_b;      
y[2].value = 0.0;
vx.add(y);
svm_node[] z = new svm_node[3];
z[0] = new svm_node();
z[0].index = color_r;        
z[0].value = 255.0;             
z[1] = new svm_node();
z[1].index = color_g;      
z[1].value = 255.0;
z[2] = new svm_node();
z[2].index = color_b;        
z[2].value = 255.0;
vx.add(z);


_prob.x[0] = (svm_node[]) vx.get(0);
_prob.x[1] = (svm_node[]) vx.get(1);