Passing parameters back and forth

[livingenzyme]

How do I pass multiple parameters back and forth between main and subroutine? Say I have the following program.


public class test {
public static void main(String[] args) {
char a=' ';
int b=1;
sub(a,b);
System.out.print(a +" " +b);
}
static void sub(char a,int b) {
a='h';
b=15;
return new Object(a,b);

}

}
Obviously, the ouput isn't going to be "h 15". What do I need to change for a and b to be passed back to main?

PS - I must say I am frustrated by java.

 

[Diancecht]

A Java method cannot return more than one parameter. You would need to encapsulate them in a new class or maybe use a Vector

Cheers,
Dian

 

[livingenzyme]

In other words, java sucks. I should have known this when I started learning it.

 

[stefanwagner]

Well, or maybe you suck? When you return something (last line):

    static void sub (char a,int b) {
        a='h';
        b=15;
        return new Object (a,b);   
    }

you have to declare it:

    static Object sub (char a,int b) {
        a='h';
        b=15;
        return new Object (a, b);   
    }

But here the compiler will have a reason to complain: There is no constructor for object which takes 2 parameters. You may use a self defined Object CI, and declare to return that:

    class CI {
        char c;
        int i;
        new CI (char c, int i) {
            this.c = c;
            this.i = i;
        }
    }

    static CI sub (char a,int b) {
        a = 'h';
        b = 15;
        return new CI (a, b);   
    }

To use that object, you have to assign the result of your methodcall to an object:

    public static void main (String[] args) {
        char a = ' ';
        int b = 1;
        CI ci = sub (a, b);
        System.out.print (ci.a + " " + ci.b);
    }

don't visit my homepage:

http://home.arcor.de/hirnstrom/minis/index.html

 

[livingenzyme]

Yes, I do suck. I can't get your example to compile.


public class test {
public static void main (String[] args) {
char a = ' ';
int b = 1;
CI ci = sub (a, b);
System.out.print (ci.a + " " + ci.b);
}

class CI {
char c;
int i;
new CI (char c, int i) {
this.c = c;
this.i = i;
}
}

static CI sub (char a,int b) {
a = 'h';
b = 15;
return new CI (a, b);
}
}

 

[stefanwagner]

Yes, you're right in 3 ways:
a) The CTOR can have a visibility modifier like 'public, private, protected' or nothing but not new (CI).
b) I didn't make visible, that the static method 'sub' needs a surrounding class.
c) I named ci.c and ci.i in the main-method ci.a and ci.b.
This is now a compilable file:

class CI {
	char c;
	int i;
	
	CI (char c, int i) 
	{
		this.c = c;
		this.i = i;
	}
}

public class CiTest
{
	static CI sub (char a, int b) 
	{
		a = 'h';
		b = 15;
		return new CI (a, b);   
	}

	public static void main (String[] args) {
		char a = ' ';
		int b = 1;
		CI ci = sub (a, b);
		System.out.print (ci.c + " " + ci.i);
	}
}

don't visit my homepage:

http://home.arcor.de/hirnstrom/minis/index.html