How can I find the sum of two numbers which are in String variables?

Question

In this code fragment, I can\'t sum a and b:

String a = \"10\";
String b = \"20\"; 
JOptionPane.showMessageDialog(null,a+b);
         


        

Answer 1

public void actionPerformed(ActionEvent arg0) 
{
    String a= txtnum1.getText(); 
    String b= txtnum2.getText(); 
    String result = "";
    try{
    int value = Integer.parseInt(a)+Integer.parseInt(b);
     result = ""+value;
    }catch(NumberFormatException ex){

     result = "Invalid input";
    }
    JOptionPane.showMessageDialog(null,result);



}

it is work