JAVA functions

 

Java function

Example 1 using of basic function:

public class Demo01 {
    public static void main(String[] args) {
        int sum = add(1,2);// call function;'1' and '2' are actual parameter
        System.out.println(sum);
    }
    public static int add(int a, int b){
      /*
      ‘public static’: modifier, to tell the compiler how to call the method 
      'int':type of return value
      'add(formal parameter: int a, int b)':function name - CamelCase rule
      
      */
        return a+b;
    }
}

Example 2 using commond pass value

package method;
​
public class Demo02 {
    public static void main(String[] args) {
        for (int i = 0; i < args.length; i++) {
            System.out.println(args[i]);
​
        }
    }
}
/*
(base) 192-168-1-104:src yanglimin$ cd method
(base) 192-168-1-104:method yanglimin$ javac Demo02.java
(base) 192-168-1-104:method yanglimin$ cd ../
(base) 192-168-1-104:src yanglimin$ java method.Demo02
(base) 192-168-1-104:src yanglimin$ java method.Demo02 LILAPE STUDIO
​
LILAPE
STUDIO
​
*/

Example 3 Variable arguments

When number of parameter is not sure, we can use variable arguments

You need to notice: the variable arguments should at the end of method parameter defenition. Here is an example

public void test(int a, int...b){//acceptable
}
public void test(int...b, int a){//unacceptable
}

Here is an example of using variable arguments:

package method;
​
public class Demo03 {
    public static void main(String[] args) {
        Demo03 demo03 = new Demo03();
        demo03.test(1,3,4,5);// you can pass different number of parameter by using 'int...a' in your method
    }
    public void test(int...a){
        for (int i = 0; i < a.length; i++) {
            System.out.println(a[i]/2);
        }
​
    }
}
​