数组的相关操作
- 在Java中,所有的数组都有一个缺省的属性length,用于获取数组中元素的个数;
- 数组的复制:System.arraycoye(Object src, int srcPos, Object dest, int destPos, int length);(file 1)
- 数组的排序:Arrays.sort();
- 在已排序的数组中查找某个元素:Arrays.binarySearch();
## file 1 ##
class ArrayTest{
public static void main(String[] args){
int arr[] = new int[]{1,2,3};
int arr1[] = new int[10];
System.arraycopy(arr,1,arr1,1,2);
for(int i = 0;i < arr1.length; i ++){
System.out.println(arr1[i]);
}
}
}
## file 2 ##
import java.util.Arrays;
class ArrayTest{
public static void main(String[] args){
int arr[] = new int[]{3,1,2};
Arrays.sort(arr);
for(int i = 0;i < arr.length; i ++){
System.out.println(arr[i]);
}
int index = Arrays.binarySearch(arr,2);
System.out.println(index);
Student ss[] = new Student[]{new Student(18,"shanghai"),
new Student(20,"guangdong"),
new Student(15,"shengz"),
new Student(30,"beijing")};
Arrays.sort(ss);
for(int i=0;i<ss.length;i++){
System.out.println(ss[i]);
}
}
}
class Student implements Comparable{
int age;
String name;
Student(int age,String name){
this.age = age;
this.name = name;
}
public String toString(){
return "age="+age+"name="+name;
}
public int compareTo(Object o){
Student s = (Student)o;
return age > s.age ? 1 : age==s.age ? 0 : -1;
}
}