初识Jjava --数组

Day6

public static void main(String[] args) {

        int[] nums;//定义一个数组
        nums=new int[10];
        nums[0]=1;
        nums[1]=2;
        nums[2]=3;
        nums[3]=4;
        nums[4]=5;
        nums[5]=6;
        nums[6]=7;
        nums[7]=8;
        nums[8]=9;
        nums[9]=10;
    //    System.out.println(nums[9]);
        //计算所有元素之和
        int sum=0;
        //获取数组长度:  arrays.length

        for (int i = 0; i < nums.length; i++) {
            sum=sum+nums[i];
        }
        System.out.println(sum);
    }

public static void main(String[] args) {

        int[] array=new int[10];
        array[0]=1;
        array[1]=2;
        array[2]=3;
        array[3]=4;
        array[4]=5;
        array[5]=6;
        array[6]=7;
        array[7]=8;
        array[8]=9;
        array[9]=10;
        for (int i=1;i<array.length;i++){
            System.out.println(array[i]);
        }
    }

public static void main(String[] args) {
        int[] array={1, 2, 3, 4, 5};

        for (int i=0;i<array.length;i++){
            System.out.println(array[i]);
        }
        System.out.println("=======================================");
        //所有元素之和
        int sum=0;
        for (int i=0;i< array.length;i++){
            sum+=array[i];
        }
        System.out.println("sum="+sum);
        System.out.println("=====================================================");
        //最大值
        int max=0;
        for (int i=0;i<array.length;i++){
            max=array[i];
        }
        System.out.println("max="+max);
    }

public static void main(String[] args) {

        int[] arrays={1,2,3,4,5};
        int[] reverse=reverse(arrays);
        pritArray(reverse);
    }
    //反转数组
    public static int[] reverse(int[] arrays){
        int[] result =new int[ arrays.length];

        //操作

        for (int i = 0,j=result.length-1; i <arrays.length ; i++,j--) {
            result[j]=arrays[i];

        }
        return result;
    }
    public static void pritArray(int[] arrays){
        for (int i = 0; i < arrays.length ; i++) {
            System.out.println(arrays[i]+"");

        }
    }

public static void main(String[] args) {
        //[4][2]

        /*
        1,2  array[0]
        2,3  array[1]
        3,4  array[2]
        4,5  array[3]
         */
        int[][] array={{1,2},{2,3},{3,4},{4,5}};

        for (int i = 0; i < array.length ; i++) {
            for (int j = 0; j <array[i].length ; j++) {
                System.out.println(array[i][j]);
            }
        }
    }

public static void main(String[] args) {

        int[] a={1,2,3,4,9999,31231,543,21,3,23};
        System.out.println(a);
        //打印数组元素Array.toStringg
        System.out.println(Arrays.toString(a));
        printArray(a);
    }
    public static void printArray(int[]a){
        for (int i = 0; i <a.length ; i++) {
            if (i==0) {
                System.out.print("[");
            }
            if (i==a.length-1) {
                System.out.print(a[i] + "]");
            }else {
                System.out.print(a[i]+",");
            }
        }
    }

public static void main(String[] args) {

        int[] a={1,2,3,4,99,777,444,3,3,8,7,6,1000};
        int[] sort= sort(a);
        System.out.println(Arrays.toString(sort));
    }
    public static int[] sort(int[]array){
        int temp=0;
        //
        for (int i = 0; i < array.length-1; i++) {
            //
            for (int j =0; j < array.length-1-i; j++) {
                if (array[j+1] > array[j]) {
                    temp = array[j];
                    array[j] = array[j+1];
                    array[j+1] = temp;
                }
            }
        }
        return array;
    }

public static void main(String[] args) {

        int[][] deter=new int[11][11];
        deter[1][2]=1;
        deter[2][10]=2;
        System.out.println("输出");
        for (int[] bai:deter){
            for (int hei:bai){
                System.out.print(hei+"\t");
            }
            System.out.println();
        }
    }

public static void main(String[] args) {

    }
    /*
    修饰符  返回值类型  方法名（。。。）{
    //方法体
    return  返回值；
    }
     */
    public String sayHello(){
        return "hello world";
    }
    public void print(){
        return;
    }
    public int max(int a,int b){
        return a>b? a:b; //三元运算符
    }