一篇文章带你入门java方法

// 方法定义
public static 方法返回值 方法名称（[参数类型 形参 ...]){
     //方法体代码;
     return 返回值;
}
// 方法调用
返回值变量 = 方法名称(实参...);

public static void main(String[] args) {
    int a = 20;
    int b = 30;
    int c = add(a,b);//方法的调用
    System.out.println(c);
}
//方法的定义
public static int add(int a,int b) {
    return a + b;
}

public static void main(String[] args) {
    int a = 20;
    int b = 30;
    int c = add(a,b);
    System.out.println("c = " + c);
    int d = add(a,c);
    System.out.println("d = "+ d);
    int e = add(c,d);
    System.out.println("e = "+ e);
}
public static int add(int a,int b) {
    return a + b;
}

public static int addInt(int a,int b) {
        return a + b;
}

public static double addDouble(double a, double b) {
        return a + b;
}

public static int add(int a,int b) {
        return a + b;
}
public static double add(double a, double b) {
    return a + b;
}

public static void main(String[] args) {
    int a = 20;
    int b = 30;
    double c = 5.4;
    double d = 7.8;
    System.out.println(add(a,b));
    System.out.println(add(c,d));
}
public static int add(int a,int b) {
    return a + b;
}
public static double add(double a, double b) {
    return a + b;
}

public static void main(String[] args) {
    int n = 5;
    int ret = fac(n);
    System.out.println("ret = " + ret);
}
//求n的阶乘
public static int fac(int n) {
    if(n == 1) {
        return 1;
    } else {
        return n * fac(n - 1);
    }
}