内容纲要

227讲方法重载（OverLoad）、可变参数、作用域

public class Test01{
    public static void main(String[] args){
        calculate(2,6);
        System.out.println(calculate(2,6));
        System.out.println(calculate(2,60.0));
        calculate(2.0,1.0);
    }
    public static int calculate(int n1, int n2){
        int sum = n1 + n2;
        return sum;
    }
    public static double calculate(double n1,int n2){
        double sum = n1 + n2;
        return sum;
    }
    public static double calculate(double n1,double n2){
        double sum = n1 + n2;
        return sum;
    }
    public static double calculate(int n1,double n2){
        double sum = n1 + n2;
        return sum;
    }
}

上面这个例子没有构成方法重载，会报错，这个是方法的重复定义。

练习题

public class OverLoadExercise{
    public static void main(String[] args){
        Exercise e = new Exercise();
        System.out.println(e.m(5));//25
        System.out.println(e.m(2,10));//20
        System.out.println(e.m("HandSome"));//HandSome
    }
}
class Exercise{
    public int m(int i){
        int res = i*i;
        return res;
    }
    public int m(int i,int j){
        int res = i*j;
        return res;
    }
    public String m(String s){
        return s;
    }
}

public class Test01{
        public static void main(String[] args){
            Exercise exercise = new Exercise();
            System.out.println(exercise.max(1,5));
            System.out.println(exercise.max(1.0,3.0));
            System.out.println(exercise.max(6.0,9.0,8.8));
        }
    }
    class Exercise{
        public int max(int i,int j){
            return i > j?i:j;
        }
        public double max(double i,double j){
            return i > j?i:j;
        }
        public double max(double i,double j,double m){
            double max1;
            max1 = j > i ? j : i;
            return max1 > m ? max1 : m;
        }
    }

可变参数

可变参数可以当作数组使用。可以通过遍历求和。！！！！

对了可变参数不能是多个数组！！！！

注意可变参数可以和普通类型的形参放一起，但是可变参数一定要放最后！

练习

public class Test01{
        public static void main(String[] args){
            HspMethod student = new HspMethod();
            System.out.println(student.showScore("李二",80,40));
            System.out.println(student.showScore("张三",10,30,60));
            System.out.println(student.showScore("王五",1,2,3,4,5));
        }
    }
    class HspMethod{
        public String showScore(String name, double... score){
            double totalScore = 0;
            for(int i = 0;i < score.length;i++){
                totalScore += score[i];
            }
            String str = name + totalScore;
            return str;
        }
    }