Objective: This assignment will give you practice with action event handling.
The programming assignment:
In this assignment you are to add functionality to the calculator created in lab 08. You don’t have to make the calculator a full function calculator. You only need to make buttons 0 ~ 9, +, -, *, / and = work.
Some programming hints:
1. Implement an action listener.
public void actionPerformed(ActionEvent e) { for (int i=0; i<=9; ++i) { if (e.getSource() == digitButton[i]) {
if (newNumber) {
display digit in tf;
newNUmber = false;
} else append digit in tf;
return;
}
}
if (e.getSource() == addButton ){ opnd1 = Double.parseDouble(tf.getText());
newNumber = true;
operator = ‘+’; return;
}
if (e.getSource() == eqButton) { opnd2 = Double.parseDouble(tf.getText()); switch (operator) { case ‘/’: res = opnd1 / opnd2; break; case ‘*’: res = opnd1 * opnd2; break; case ‘-‘: res = opnd1 - opnd2; break;
case ‘+’: res = opnd1 + opnd2; break;
}
display(""+res); newNumber = true; return;
}
}
2. Register the action listener with all buttons.
