Re: my calculator has problems

[umen]

Hi,
Number1 is NSButton. result is the NSTextField. I assign string to number1 because with strings I can append other numbers and assign this new number to number1 again, then I use doubleValue to get a double from this string. It's exactly what else{} is doing at all button methods. Or there is another/better way to do that not using strings?
-------- Original Message --------
On 9 de abr de 2016 01:02, Germán Arias wrote:
>  
>  
>   Hi,
>   
>  
>   
>  I have not clear what is "number1". But in method "-add" you assign a
>   
>  string to this variable, so this become a string object. Then, later,
>   
>  you call "-setDoubleValue:" at "number1" as if it was an NSTextField
>   
>  object. If this is an NStextField object, then you should do (in method
>   
>  "-add"):
>   
>  
>   
>  [number1 setDoubleValue: 0];
>   
>  
>   
>  Hope this help.
>   
>  Germán
>   
>  
>   
>  El vie, 08-04-2016 a las 15:01 -0400, umen escribió:
>   
>  > Hi people,
>   
>  > 
>   
>  > I'm trying to write a basic calculator using GNUstep+ObjC and I get stucked. I really don't know where is the problem in my code. May you help me?
>   
>  > 
>   
>  > 
>   
>  > I'm sending here what I have implemented until now:
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > @interface UCalc : NSObject
>   
>  > 
>   
>  > {
>   
>  > 
>   
>  > char operation; //just a char to validate the operation
>   
>  > 
>   
>  > id number1, number2; //number1 = the current button pressed, number2
>   
>  > = the old number
>   
>  > 
>   
>  > id result; //the calculator display
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > - (void) Add: (id)sender;
>   
>  > 
>   
>  > @end
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > @implementation UCalc
>   
>  > 
>   
>  > - (void) Add: (id)sender
>   
>  > 
>   
>  > {
>   
>  > 
>   
>  > operation = '+';
>   
>  > 
>   
>  > number2 = number1; //when you press the add button the current
>   
>  > number becomes the old number
>   
>  > 
>   
>  > number1 = @"0";
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > - (void) Button0: (id)sender
>   
>  > 
>   
>  > {
>   
>  > 
>   
>  > number1 = @"0";
>   
>  > 
>   
>  > [result setStringValue: number1];
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > - (void) Button1: (id)sender
>   
>  > 
>   
>  > {
>   
>  > 
>   
>  > //if there is no number yet
>   
>  > 
>   
>  > if (number1 == nil || [number1 isEqual: @"0"]){
>   
>  > 
>   
>  > [result setStringValue: @""];
>   
>  > 
>   
>  > number1 = @"1";
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > //else append the current number in itself, so we can get number > 9
>   
>  > 
>   
>  > else{
>   
>  > 
>   
>  > number1 = [number1 stringByAppendingFormat: @"1"];
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > [result setStringValue: number1];
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > - (void) Button2: (id)sender
>   
>  > 
>   
>  > {
>   
>  > 
>   
>  > if (number1 == nil || [number1 isEqual: @"0"]){
>   
>  > 
>   
>  > [result setStringValue: @""];
>   
>  > 
>   
>  > number1 = @"2";
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > else{
>   
>  > 
>   
>  > number1 = [number1 stringByAppendingFormat: @"2"];
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > [result setStringValue: number1];
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > All the others number buttons are implemented in the same way...
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > The problem is in Equal button:
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > - (void) Equal: (id)sender{
>   
>  > 
>   
>  > switch(operation){
>   
>  > 
>   
>  > case '+':
>   
>  > 
>   
>  > //trying to do this: number1 = number2 + number1 and then print
>   
>  > in the display result
>   
>  > 
>   
>  > [number1 setDoubleValue: [number2 doubleValue] + [number1
>   
>  > doubleValue]];
>   
>  > 
>   
>  > [result setStringValue: number1];
>   
>  > 
>   
>  > break;
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > }
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > I already have created the window in Gorm, so everything is
>   
>  > implemented there. The problem in this code is in the number1 =
>   
>  > number2 + number1 in Equal method, I don't know why it's not assigning
>   
>  > to number1 the operation correctly and then result working correctly.
>   
>  > Any idea about what I'm doing wrong? Everything?
>   
>  > 
>   
>  > 
>   
>  > 
>   
>  > Sorry my english. Thanks.
>   
>  > _______________________________________________
>   
>  > Discuss-gnustep mailing list
>   
>  > Discuss-gnustep@gnu.org
>   
>  > https://lists.gnu.org/mailman/listinfo/discuss-gnustep
>   
>  
>   
>  
>   
>  
>