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

try: Integer.parseInt(a)+Integer.parseInt(b)

 String a= txtnum1.getText();
 String b= txtnum2.getText(); 
 JOptionPane.showMessageDialog(null,Integer.parseInt(a)+Integer.parseInt(b));