Iterations - finding the same value for 2 variables

[Arjun Bajaj]

Hi everyone.....

I'm trying to make a program which can calculate the turning effects of rod.....

i have made this :

  class iteration {
public static void main (String args[]) {

int force = 0;
int distance = 18;

int force2 = 0;
int distance2 = 9;

int moment2;
int finalmoment;


for (int moment = force * distance; moment < 100;) {

moment = force * distance;
moment2 = force2 * distance2;

System.out.println ("Moment 1 = " + moment);
System.out.println ("Moment 2 = " + moment2);

force++;
force2++;

}

}
}  

but i want to calculate the value which the program will get same for both moment and moment2


i tried this but i didn't work.... :

   
if (moment = moment2) {
finalmoment = moment;
}

System.out.println ("Final Moment = " + finalmoment);

 

this tells me that i need a boolean rather than an int but it doesn't even allow casting...

so what should i do to get that value which is same for both the variables???

please help......its my physics homework.......

[Joanne Neal]

= is an assignment operator
== is a comparison operator

[David Newton]

In other words: = != ==.

[Arjun Bajaj]

hey,

i tried that but then also it didn't work......

see my current code is :

    
class iteration {
public static void main (String args[]) {

int force = 2;
int force2 = 2;

int distance = 18;
int distance2 = 9;

int moment;
int moment2;

for (moment = force * distance; moment < 1000000;) {

moment = force * distance;
moment2 = force2 * distance2;

if (moment == moment2) {
System.out.println ("Final Turning Effect = " + moment);
}

force++;
force2++;

}

}
}

I dont get any value in the command line.......

What should i do???

please help.......

[David Newton]

Fix your code's logic--it's almost certainly not doing what you think it is. Printing out the iteration count and the two variables you're modifying might be a good place to start.

[Rob Spoor]

Let's iterate a bit manually, shall we?

force == 2, distance == 18 => moment == 36
force2 == 2, distance2 == 9 => moment2 == 18

force == 3, distance == 18 => moment == 54
force2 == 3, distance == 9 => moment == 27

force == 4, distance == 18 => moment == 72
force2 == 4, distance == 9 => moment == 36


As you see, the way your code works now moment will always be twice as large as moment2.

So you want to find a moment and moment2 that are equal? Then you should increment either force or force2:

class iteration
{
    public static void main (String args[])
    {
        int force = 2;
        int force2 = 2;

        int distance = 18;
        int distance2 = 9;

        int moment;
        int moment2;

        moment = force * distance;
        while (moment < 1000000)
        {
            moment = force * distance;
            moment2 = force2 * distance;

            if (moment == moment2)
            {
                System.out.println ("Final Turning Effect = " + moment);
                // break out of the loop
                break;
            }
            else if (moment < moment2)
            {
                // increase only force so moment becomes larger
                force++;
            }
            else
            {
                // increase only force2 so moment2 becomes larger
                force2++;
            }
        }
    }
}

I know find that moment == 36 will break the loop.

If you don't want that break in there you can increase both force and force2 instead. You then get all multiples of 18 except for 0 and 18 itself (since moment will always be larger than 18).

[David Newton]

... Seems like giving a hint would have been enough.

[Arjun Bajaj]

hey thanks,
joanne neal, david newton and rob prime for answering.......


hey rob thanks......

i finally solved the problem using your suggestion.......

i just removed the break; method.....and in place of that i put force++

and i added a limit to the while condition and then i got like 100,000 values where those objects can be balanced......

thnx a lot everyone.....