JavaSE复习日记 : 方法的调用和方法的重载

<span>/*</span><span> *                          方法的调用和方法重载
 </span><span>*/</span><span>/*</span><span> *      什么是方法?
 *          方法就是一个有名字的代码段;
 *      方法的调用:
 *          在方法里调用另外一个方法里面的东西就是方法调用;
 *          或者可以认为"另外一个方法的名字()"就是方法的调用;
 *      方法的重载:
 *          就是在main方法外写了多个方法名相同,但是形参列表不同的方法,在main方法中调用这个方法时括号内写上实参,程序会默认调用实参和调用方法里形参相匹配的方法;
 </span><span>*/</span><span>//</span><span>                              方法形式和方法的类部调用</span><span>/*</span><span>public class JavaSE{
    public static void main(String[] args){
        JavaSE.Method_1();//方法的调用就是:类名.方法名(实参列表);
        Method_2(1,2);//main方法调用这个类里面的静态方法也可以这么写;
        Method_3(5,5);
    }
    public static void Method_1(){
        System.out.println( "我很帅" );
    }
    public static void Method_2(int a,int b){
        int c = a + b;
        System.out.println( c );
    }
    public static int Method_3(int e,int d){//注意这里static后面跟的是int,是返回值类型,这是方法最后必须写return语句;
        int f = e + d;
        System.out.println( f );
        return f;//return语句在有返回值类型的时候必须有返回值,不然会报错;
    }
}
</span><span>*/</span><span>//</span><span>-------------------------------------------------------------------------

</span><span>//</span><span>                          方法的重载</span><span>public</span><span>class</span><span> JavaSE{
    </span><span>public</span><span>static</span><span>void</span><span> main(String[] args){
       Method_4(</span><span>1</span>,<span>1.0</span>);<span>//</span><span>这里1是int型的,1.0是double型的,结果是2.0,结果自动转换为double型</span>       Java.sum(<span>2</span>,<span>1</span>);<span>//</span><span>调用外部类的方法必须是:外部类名.方法名(实参列表);</span><span>    }
    </span><span>public</span><span>static</span><span>void</span> Method_4(<span>int</span> a,<span>int</span><span> b){
        </span><span>int</span> c = a +<span> b;
    }
    </span><span>public</span><span>static</span><span>void</span> Method_4(<span>int</span> a,<span>double</span><span> b){
        System.</span><span>out</span>.println( a +<span> b );
    }
}

</span><span>class</span><span> Java{
    </span><span>public</span><span>static</span><span>void</span> sum(<span>int</span> a,<span>int</span><span> b){
        System.</span><span>out</span>.println( a +<span> b );
    }
    </span><span>public</span><span>static</span><span>void</span> sum(<span>int</span> a,<span>double</span><span> b){
        System.</span><span>out</span>.println( a -<span> b );
    }
}</span>