java ArrayList的实现
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java ArrayList的实现
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public class ArrayListDemo {public int size=0;//當(dāng)前數(shù)組容量public int capacity=2;//默認(rèn)容量public Object[] objects = new Object[capacity];public ArrayListDemo() {}public void add(Object object) {//檢查數(shù)組是否已經(jīng)裝滿,如果數(shù)組裝滿,數(shù)組容量擴(kuò)大一倍if(capacity==size){capacity = this.capacity*2;objects = Arrays.copyOf(objects,capacity);}//添加數(shù)據(jù)objects[size++]=object;}public void delete(Object object) {//刪除指定元素//遍歷數(shù)組int temp = 0;for(int i = 0;i<size;i++){if(object==objects[i]){temp = i;break;}}for(int j=temp;j<size;j++){objects[temp]=objects[temp+1];}size--;
// System.arraycopy(objects, temp+1, objects, temp, size-temp);
// size--;
}@Overridepublic String toString() {//重寫方法String str = "[";for (int i = 0;i<size;i++){str=str+" "+objects[i];}str=str+" "+"]";return str;}public void set(int i, Object object) {//修改數(shù)組if(i<0||i>capacity){System.out.println("超出數(shù)組大小");}for(int j=0;j<capacity;j++){if(i==j){objects[i-1]=object;break;}}}
} public class ArrayListTest {public static void main(String[] args) {ArrayListDemo arrayListDemo = new ArrayListDemo();arrayListDemo.add(1);arrayListDemo.add("AA");arrayListDemo.add("##");arrayListDemo.add(6);arrayListDemo.add(5);System.out.println(arrayListDemo.size);//測試數(shù)組當(dāng)前元素數(shù)量System.out.println(arrayListDemo);//測試查詢//arrayListDemo.delete(6);//測試刪除//System.out.println(arrayListDemo);//arrayListDemo.set(3,"hello");//測試修改//System.out.println(arrayListDemo);
}
}
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轉(zhuǎn)載于:https://www.cnblogs.com/5aixin/p/11443846.html
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