【Java基础】方法基础

方法的四种样式：

　　无参无返；

　　无参有返；

　　有参无返；

　　有参有返；

public class MethodDefine {

    public static void main(String[] args) {

        //方法的调用
        method1();

        int result = method2();
        System.out.println("a与b的和是：" + result);

        method3(1,2);

        int sum = method4(1,2);
        System.out.println("a与b的和是：" + sum);
    }

    //无参无返
    public static void method1(){
        int a = 1;
        int b = 2;
        int sum = a + b;
        System.out.println("a与b的和是：" + sum);
    }
    //无参有返
    public static int method2(){
        int a = 1;
        int b = 2;
        int sum = a + b;
        return  sum;
    }

    //有参无返
    public static void method3(int a, int b){
        int sum = a + b;
        System.out.println("a与b的和是：" + sum);
    }
    //有参有返
    public static int method4(int a, int b){
        int sum = a + b;
        return sum;
    }
}

练习：定义一个方法，求出1~100之间整数的累加和

public class Demo02MethodSum {

    public static void main(String[] args) {
        System.out.println("1-100的累加和是：" + getSum());
    }

    public static int getSum() {
        int sum = 0;
        for (int i = 1; i <= 100; i++) {
            sum = sum + i;
        }
        return sum;
    }
}