JAVA Day10

JAVA Day10

递归

ps:参数小的情况用递归

//5的阶层
package struct;

import static java.lang.System.out;

public class Day8 {
    public static void main(String[] args) {
        out.println(f(5));

        }
    public static int f(int n){
        if(n==1){
            return 1;
        }else{
            return n*f(n-1);
        }
    }
}

//简单计算器
package struct;

import java.util.Scanner;
public class Day8 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
            int i = scanner.nextInt();
        String str = scanner.next();
            int j = scanner.nextInt();
        switch (str){
            case"+":
                System.out.println(add(i,j));
                break;
            case "-":
                System.out.println(sub(i,j));
                break;
            case "*":
                System.out.println(mult(i,j));
                break;
            case "/":
                System.out.println(divi(i,j));
                break;
        }

        scanner.close();

        }
    public static int add(int i,int j){
        return i+j;
    }
    public static int sub(int i,int j){
        return i-j;
    }
    public static int mult(int i,int j){
        return i*j;
    }
    public static double divi(double i,double j){
        return i/j;
    }

}

数组

数组的定义

数组声明创建

int[] nums;//定义
nums = new int[10];//创建一个数组nums.length=10
//赋值
nums[1]=1;//下标1的值为1