基本概念

class point{
    //java的函数必须定义到 类 里面
    //有两种函数
    //普通的public函数
    public int f(){
        return 0 ;
    }
    //加static的函数 类似于全局函数（ 加static的变量类似于全局变量）
    //加static相当于绑定到这个类本身
    public static int g(){
        return 0;
    }

}

类是static，函数也必须是static

输出最大值

package test1;

import java.util.Scanner;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int a = sc.nextInt();
        int b = sc.nextInt();

        System.out.println(max(a,b));
    }

   public static int max(int a,int b){
        return Math.max(a,b);
   }
}

为二维数组赋初值

package test1;

import java.util.Arrays;


public class Main{
    public static void main(String[] args) {
        int[][] a = new int[5][5];
        fill(a, 3);
        System.out.println(Arrays.deepToString(a));
    }

        private static void fill ( int[][] a, int val) {
            for (int i = 0; i < a.length; i++)
                for (int j = 0; j < a[i].length; j++)  a[i][j] = val;


        }

}

初始二维数组的行，列，值

package test1;

import java.util.Arrays;


public class Main{
    public static void main(String[] args) {
        int [][] b = getArray2d(2,3,6);
        System.out.println(Arrays.deepToString(b));
    }

    private static int[][] getArray2d(int col,int row,int val){
        int [][]a = new int[col][row];
        for (int i = 0; i < col; i++) {
            for (int j = 0; j < row; j++) {
                a[i][j] = val;
            }
        }
        return a;
    }

}

package test1;

//相当于定义了全局变量
class Argument{
    public static int x = 1;
    public final static int y = 1;
}


public class Main{
    public static void main(String[] args) {
        System.out.println(Argument.x);//静态变量访问 用类名 普通变量和普通函数 用具体的实例访问
    }

}