初步学习java的方法 Day5

命令行传递参数

示例图片：

初识java Day5

public static void main(String[] args) {

        int i=0;
        while (i<100){
            i+=1;
            System.out.println(i);
            if (i==30){
                break;
            }
        }
    }

public static void main(String[] args) {

        int i=0;
        while (i<100){
            i++;
            if (i%5==0){
                System.out.println( );
                continue;
            }
            System.out.print("\t"+i);
        }
    }

public static void main(String[] args) {

        //打印三角形  5行
        int i,j;
        for (i=1;i<=5;i++){
            for (j=5;j>=i;j--){
                System.out.print(" ");
            }
            for (j=1;j<=i;j++){
                System.out.print("#");
            }
            for (j=1;j<i;j++){
                System.out.print("#");
            }
            System.out.println();
        }
    }

public static void main(String[] args) {

        int sum=add(1,2,7);
        System.out.println(sum);
        //test();

    }
    //加法
    public static int add(int a,int b){
        return a+b;
    }
    public static int add(int q,int w,int e){
        return q+w+e;
    }
    public static int add(int z,int x,int c,int v){
        return z+x+c+v;
    }
    /*
    public static void test(){
        for (int i = 0; i <= 1000; i++) {
            if (i%5==0){
                System.out.print(i+"\t");
            }
            if (i%(3*5)==0){
                System.out.print("\n");
            }
        }
    }
    */

 public static void main(String[] args) {

        int max=max(10,10);
        System.out.println(max);
    }
    public static int max(int m,int n){
        int result=0;

        if (m==n){
            System.out.println("m==n");
            return 0;
        }
        if (m>n){
            result=m;
        }
        if (n>m){
            result=n;
        }
        return result;
    }

public static void main(String[] args) {

        double max=max(9.0,8);
        System.out.println(max);
    }
    public static int max(int num1, int num2){
        int result=0;
        if (num1>num2){
            result=num2;
        }
        if (num1>num2){
            result=num1;
        }
        if (num1==num2){
            System.out.println("uuu");
            return 0;
        }
        return result;
    }
    public static double max(double num1, double num2){
        double result=0;
        if (num1>num2){
            result=num2;
        }
        if (num1>num2){
            result=num1;
        }
        if (num1==num2){
            System.out.println("uuu");
            return 0;
        }
        return result;
    }

public static void main(String[] args) {

        //args.length 数组长度
        for (int i=0;i< args.length;i++){
            System.out.println("args["+i+"]:"+args[i]);
        }
    }

public static void main(String[] args) {

        Demo05 demo05=new Demo05();
        demo05.test(1,2,3,4,555,6);
    }
    public void test(int... i){
        System.out.println(i[0]);
        System.out.println(i[1]);
        System.out.println(i[2]);
        System.out.println(i[3]);
        System.out.println(i[4]);
        System.out.println(i[5]);
    }

public static void main(String[] args) {

        //调用可变参数的方法
        printMax(34,3,3,2,56,5);
        printMax(new double[]{1,2,3});
    }
    public static void printMax(double... numbers){
        if (numbers.length==0){
            System.out.println("NO argument passed");
            return;
        }
        double result=numbers[0];
        //排序
        for (int i=1;i< numbers.length;i++){
            if (numbers[i]>result){
                result=numbers[i];
            }
        }
        System.out.println("The max value is"+result);
    }

public static void main(String[] args) {
        System.out.println(f(5));
    }
    public static int f(int n){
        if (n==1){
            return 1;
        }else {
            return n*f(n-1);
        }
    }

public static void main(String[] args) {
        System.out.println("请选择你要进行的计算：+ ，- ，* ，/ ");
        Scanner scanner=new Scanner(System.in);
        String js= scanner.next();

        int m,n;
        switch (js){
            case "+":
                System.out.println("请输入第一个数：");
                m = scanner.nextInt();
                System.out.println("请输入第二个数：");
                n=scanner.nextInt();
                System.out.println("结果为："+m+"+"+n+"="+(m+n));
                break;
            case "-":
                System.out.println("请输入第一个数：");
                m = scanner.nextInt();
                System.out.println("请输入第二个数：");
                n=scanner.nextInt();
                System.out.println("结果为："+m+"-"+n+"="+(m-n));
                break;
            case "*":
                System.out.println("请输入第一个数：");
                m = scanner.nextInt();
                System.out.println("请输入第二个数：");
                n=scanner.nextInt();
                System.out.println("结果为："+m+"*"+n+"="+(m*n));
                break;
            case "/":
                System.out.println("请输入第一个数：");
                m = scanner.nextInt();
                System.out.println("请输入第二个数：");
                n=scanner.nextInt();
                System.out.println("结果为："+m+"/"+n+"="+(m/n));
                break;
            default:
                System.out.println("请输入正确的符号");
        }
    }