Sub Programs Demo

import java.util.Scanner;

class demo1 {
    public static int i = 0;
    public static int j = 0;
    public static void main(String[] args) {
        // Local variable i
        int i;
/*
        // Calling sub program
        sub1();

        // Calling sub program within another sub program
        sub2();
*/
        // Can other sub programs access the
        // local variable in main()?
        i = 1;
        j = 1;
        System.out.printf("main: %d\n", i);
        sub3();
        System.out.printf("main after sub3: %d %d\n", i,j);

        // Can other sub programs access the same
        // global variable j?
        i = 1;
        j = 1;
        System.out.printf("main: %d\n", j);
        sub4();
        System.out.printf("main after sub4: %d %d\n", i,j);
/*
        // Test for sending parameters
        System.out.println("Using 3 and 4 as input parameters.");
        sub5(3, 4);
        System.out.println("Using 3 and 4 as input parameters.");
        sub5(4, 8);
        int X, Y, P, Q;
        X = 2;
        Y = 3;
        P = 4;
        Q = 5;
        // Variables can be used as parameters too
        System.out.println("Using P and Q as input parameters.");
        sub5(P, Q);
        // Variables with the same name as the local variables
        // can be used too! They are different local variables
        System.out.println("Using X and Y as input parameters.");
        sub5(X, Y);
        System.out.println("Using Y and X as input parameters.");
        sub5(Y, X);


        // Test for return value
        // Local variable b
        int b;
        b = sub6(6, 11);
        System.out.printf("Result from sub6 is %d\n", b);
        System.out.printf("Result from sub6 is %d\n", sub6(7, 21));
*/
    }

    public static void sub1() {
        // Test for calling sub programs
        System.out.println("Sub1");
    }

    public static void sub2() {
        // Test for calling sub programs from
        // other sub programs
        sub1();
        System.out.println("Sub2");
        sub1();
    }

    public static void sub3() {
        // Test for global variables
        // and local variables inside ANOTHER method
        i = 4;
        j = 4;
        System.out.printf("sub3: %d %d\n", i, j);
    }

    public static void sub4() {
        // Test for global variables and
        // local variables inside the method
        int j;
        i = 5;
        j = 5;
        System.out.printf("sub4: %d %d\n", i, j);
    }

    public static void sub5(int X, int Y) {
        // Test for Parameters
        for (int i = 1; i <= X; i++) {
            for (int j = 1; j<=Y; j++) {
                System.out.print("*");
            }
            System.out.println();
        }

    }

    public static int sub6(int X, int Y) {
        int result;
        result = X + Y * 4;
        return result;
    }

}