String won't copy to array

Question

I had to create an applet that would take in two binary numbers from the keyboard and would add/subtract/multiply them. To do this we needed an int array. But when i tried doing the method shown to us, it didnt work and it would literally output garbage. It was already due and i submitted it as is but this'll bug me unless i figure it out. The calculations should work (i think) but once i get the array problem fixed i could debug that. Thanks in advance.
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class proj2 extends JApplet implements ActionListener{
    JLabel p1, p2,answer;
    JTextField i1,i2;
    JButton plus, minus, multi;
    public void init(){
        p1=new JLabel("Enter first integer");
        p2=new JLabel("Enter second integer");
        i1=new JTextField(20);
        i2=new JTextField(20);
        plus=new JButton("+");
        minus=new JButton("-");
        multi=new JButton("*");
        answer=new JLabel("Answer is          ");
        JPanel north=new JPanel();
        north.setLayout(new GridLayout(2,2));
        north.add(p1);
        north.add(i1);
        north.add(p2);
        north.add(i2);
        JPanel south=new JPanel();
        south.setLayout(new GridLayout(1,3));
        south.add(plus);
        south.add(minus);
        south.add(multi);
        Container c=getContentPane();
        c.setLayout(new BorderLayout());
        c.add(north,BorderLayout.NORTH);
        c.add(answer,BorderLayout.CENTER);
        c.add(south,BorderLayout.SOUTH);
        plus.addActionListener(this);
        minus.addActionListener(this);
        multi.addActionListener(this);
        }//end init
            public void actionPerformed(ActionEvent x){
                String a=i1.getText();
                String b=i2.getText();
                int[] top=new int[20];
                int[] bottom=new int[20];
                int[] ans=new int[20];
                int[] one=new int[1];
                one[0]=1;
                int len=a.length();
                int len2=b.length();
                for (int i=len-1;i>=0;i--)
                        char c=a.charAt(i);
                        top[len-i]=(c-48);
                for (int i=len2-1;i>=0;i--)
                        char c=b.charAt(i);
                        bottom[len2-i]=(c-48);
                if (x.getSource()==plus){
                ans=addbin(top,bottom);
                answer.setText("The sum of "+top+" and "+bottom+" is "+ans+".");}
                else if (x.getSource()==minus){
                bottom=flipbits(bottom);
                bottom=addbin(bottom,one);
                ans=addbin(top,bottom);
                answer.setText("The difference of "+a+" and "+b+" is "+ans+".");}
                else {
                for(int i=0;i<20;i++)
                    if (bottom==1)
ans=addbin(ans,top);
top=shift(top);
answer.setText("The product of "+a+" and "+b+" is "+ans+".");
}//end actionPerformed
public int[] addbin(int[] x, int[] y){
int carry=0;
int[] ans=new int[20];
for(int i=0;i<20;i++)
int sum=x[i]+y[i]+carry;
ans[i]=sum%2;
carry=sum/2;
return ans;
}//end addbin
public int[] flipbits(int[] x){
for(int i=0;i<20;i++)
x[i]=(x[i]+1)%2;
return x;
}//end flipbits
public int[] shift(int[] x){
int len=x.length;
int[] newarray=new int[len+1];
for(int i=0;i<len;i++)
newarray[i]=x[i];
newarray[len]=0;
return newarray;
}//end shift
}//end class

Answer 1

jlicata89 wrote:
int[] ans=new int[20];
answer.setText("The sum of "+top+" and "+bottom+" is "+ans+".");}
answer.setText("The difference of "+a+" and "+b+" is "+ans+".");}
answer.setText("The product of "+a+" and "+b+" is "+ans+".");
You can't just append an array to a string. Arrays don't have a custom "toString" method, so its string representation is the default one, which looks like "garbage" to you. Depending on what you want to do, you can use Arrays.toString(), or write a custom method to turn it into a string representation of your choice.
l33tard wrote:
Try changing all occurrences of this:
top[len-i]=(c-48);to:
top[len-i] = (int)(c) - 48;
That is completely useless. char's are automatically promoted to int's.