学习 资源1

学习资源 2

1、数学工具类

import com.test.*;import java.util.Random;
import java.util.RandomAccess;public class Main {public static  void main(String [] argv) throws Exception {System.out.println(Math.pow(5,3));//125.0System.out.println(Math.abs(-198.6));//198.6System.out.println(Math.min(7,90));//7System.out.println(Math.max(90,7));//90System.out.println(Math.sqrt(36));//6.0System.out.println(Math.sin(Math.PI/2));//1.0System.out.println(Math.tan(Math.PI/2));//1.633123935319537E16   有误差System.out.println(Math.log10(100));//2.0System.out.println(Math.log(Math.E));//1.0System.out.println(Math.ceil(4.6));//5.0System.out.println(Math.floor(4.5));//4.0Random random=new Random();System.out.println( random.nextInt(100));//98  随机数，再运行一次结果不一样}
}

2、数组工具类

import com.test.*;import java.util.Arrays;public class Main {public static  void main(String [] argv)  {int arr[]=new int[]{1,2,3,4,5,6,7,9,8};System.out.println(Arrays.toString(arr));//[1, 2, 3, 4, 5, 6, 7, 9, 8]Arrays.sort(arr);System.out.println(Arrays.toString(arr));//[1, 2, 3, 4, 5, 6, 7, 8, 9]int b[]=Arrays.copyOf(arr,5);System.out.println(Arrays.toString(b));//[1, 2, 3, 4, 5]int c[]=Arrays.copyOfRange(arr,2,5);System.out.println(Arrays.toString(c));//[3, 4, 5]int d[]=new int[10];System.arraycopy(arr,2,d,3,2);//[0, 0, 0, 3, 4, 0, 0, 0, 0, 0]System.out.println(Arrays.toString(d));//[0, 0, 0, 3, 4, 0, 0, 0, 0, 0]System.out.println(Arrays.binarySearch(arr,5));//4System.out.println(Arrays.equals(arr,c));//falseArrays.fill(arr,2);System.out.println(Arrays.toString(arr));//[2, 2, 2, 2, 2, 2, 2, 2, 2]int e[][]=new int[][]{{1,2},{2,3}};int f[][]=new int[][]{{1,2},{2,3}};System.out.println(Arrays.deepToString(e));//[[1, 2], [2, 3]]System.out.println(Arrays.deepEquals(e,f));//true}
}