Getting Backspace on a java calculator program to work

[marylanddem]

The following code is for a java calculator program. The code compiles, but I can't get the backspace button to work.

This is the code that calls for the backspace function:

if(i==18)
{ if(lcd.getText().length()<=1)
op1 = (lcd.getText().length() - 1);

}

The code for the calculator is attached. Any insight on how to get the backspace to work?

[pbrockway2]

I can't get the backspace button to work.

What does "work" mean? In particular what was the intention of this line:

op1 = (lcd.getText().length() - 1);

I only glanced at you code, but op1 seems to be a double value (representing the first operand of a calculation?), but in this line you are setting it equal to one less than the length of a string. It's hard to see why.

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Also I noticed code like

String arg = e.getActionCommand();
if (arg == "Exit")

just before you switch on the index of the source widget within the keys array. It is a good idea to use the string method equals() to compare strings. == tests for string identity rather than equality in the sense of being made up of the same characters in the same order.