Detailed Explanation of Class Arrays and Class Math in Java
- 2021-07-09 07:58:14
- OfStack
Arrays (Array Utility Class)
Encapsulated classes in Java provide a large number of static methods for users to use arrays.
Guide package: import java. util. Arrays
1. Arrays. toString (Array)//The return value is a string enclosed by [], and the elements in the array are placed in []
int[] arr=new int[]{1,2,3,4};
String str=Arrays.toString(arr);
System.out.println(str);
--------------------------------
[1,2,3,4]
2. Arrays. sort (Array)//No return value, sorts the array, (ascending from small to large) the array has changed
int[] arr=new int[]{3,27,46,1,48};
// String str=Arrays.toString(arr);
// System.out.println(str);
Arrays.sort(arr);
for(int i=0;i<arr.length;i++){
System.out.print(arr[i]);
}
===========================
1 3 27 46 48
Math (Mathematics)
Guide package: import java. lang (omitted)
a. Math. abs (numeric value)//Returns the absolute value of the numeric value
b. Math. ceil (numeric value)//Returns upward rounding of a numeric value
c. Math. floor (numeric)//Returns downward rounding of an array
d. Math. roud (numeric value)//Returns a numeric value rounded by 4
e. Math. PI//Value of pi