How do I check if the content of a variable is numeric? - page 4
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You really like complication . If the goal is just to process real numbers, use StringToDouble() and a processing of special case 0.
That was the initial solution:
If you don't expect the value to ever be 0, type-cast the string to a double and test that it isn't equal to 0.
However, the OP wanted to be able to deal with distinguishing whether 0 was the entered value, or if 0 was the result of the string being an invalid number. Both "0" and "sfdlgkjsflkjdsklfsd" are going to result in 0 with StringToDouble() or (double).
This was unacceptable to the OP which then spawned this subsequent discussion.
That was the initial solution:
However, the OP wanted to be able to deal with distinguishing whether 0 was the entered value, or if 0 was the result of the string being an invalid number. Both "0" and "sfdlgkjsflkjdsklfsd" are going to result in 0 with StringToDouble() or (double).
This was unacceptable to the OP which then spawned this subsequent discussion.
Simplified example :
if(value==0)
{
if(inputs=="0" || inputs=="0.0")
{
//--- all is ok
}
else
{
//--- wrong inputs
}
}
That's why I said "and a processing of special case 0."
Simplified example :
if(value==0)
{
if(inputs=="0" || inputs=="0.0")
{
//--- all is ok
}
else
{
//--- wrong inputs
}
}
And what about 0.00?
Or +0.00?
Or .0?
Yep, that is a problem.
You could do a string comparison if the cast value = 0
i.e. if(cast_value == 0 && str_value == "0")
But you would have to think about 0.0 or 0.00 being entered.
You could burst the string into a character array and test each character.
Depends how important this is.
And what about 0.00?
Or +0.00?
Or .0?
That's why I said "Simplified example". I will not do the job for the OP.
It is an interesting exercise, nevertheless i.e. is it better to have a list of possible variations of "0", or just test everything?
The former is arguably quicker but at the risk of missing a legitimate variation.
However, how important is speed when it should only be tested on a CHARTEVENT_OBJECT_ENDEDIT?
Regardless, I'm sure the OP now has plenty to go on!
It is an interesting exercise, nevertheless i.e. is it better to have a list of possible variations of "0", or just test everything?
The former is arguably quicker but at the risk of missing a legitimate variation.
However, how important is speed when it should only be tested on a CHARTEVENT_OBJECT_ENDEDIT?
Regardless, I'm sure the OP now has plenty to go on!
Or using regular expression :-D
You could also ask to input zero as "0" and reject all other cases.
Or using regular expression :-D
Personally, I would be taking an approach like this:
Once ENDEDIT happens, cast the OBJ_TEXT into a double and then push it back into the edit box as a string (using StringFormat() if I wanted to control the format). User will immediately see the outcome of their actions and either change it if it doesn't suit their needs, or leave it.
e.g.
#define EDIT_BOX "EditBox"
int OnInit()
{
ObjectCreate (0, EDIT_BOX, OBJ_EDIT, 0, 0, 0);
ObjectSetInteger(0, EDIT_BOX, OBJPROP_XDISTANCE, 200);
ObjectSetInteger(0, EDIT_BOX, OBJPROP_YDISTANCE, 200);
ObjectSetInteger(0, EDIT_BOX, OBJPROP_XSIZE, 100);
ObjectSetInteger(0, EDIT_BOX, OBJPROP_YSIZE, 20);
ObjectSetInteger(0, EDIT_BOX, OBJPROP_ALIGN, ALIGN_CENTER);
ObjectSetString (0, EDIT_BOX, OBJPROP_TEXT, "Enter Value");
return(INIT_SUCCEEDED);
}
void OnDeinit(const int reason)
{
ObjectDelete(0, EDIT_BOX);
}
void OnChartEvent(const int id, const long& lparam, const double& dparam, const string& sparam)
{
if(id==CHARTEVENT_OBJECT_ENDEDIT && sparam==EDIT_BOX)
{
double value = (double) ObjectGetString(0, EDIT_BOX, OBJPROP_TEXT);
ObjectSetString(0, EDIT_BOX, OBJPROP_TEXT, (string)value);
}
}
Personally, I would be taking an approach like this:
Once ENDEDIT happens, cast the OBJ_TEXT into a double and then push it back into the edit box as a string (using StringFormat() if I wanted to control the format). User will immediately see the outcome of their actions and either change it if it doesn't suit their needs, or leave it.
e.g.
#define EDIT_BOX "EditBox"
int OnInit()
{
ObjectCreate (0, EDIT_BOX, OBJ_EDIT, 0, 0, 0);
ObjectSetInteger(0, EDIT_BOX, OBJPROP_XDISTANCE, 200);
ObjectSetInteger(0, EDIT_BOX, OBJPROP_YDISTANCE, 200);
ObjectSetInteger(0, EDIT_BOX, OBJPROP_XSIZE, 100);
ObjectSetInteger(0, EDIT_BOX, OBJPROP_YSIZE, 20);
ObjectSetInteger(0, EDIT_BOX, OBJPROP_ALIGN, ALIGN_CENTER);
ObjectSetString (0, EDIT_BOX, OBJPROP_TEXT, "Enter Value");
return(INIT_SUCCEEDED);
}
void OnDeinit(const int reason)
{
ObjectDelete(0, EDIT_BOX);
}
void OnChartEvent(const int id, const long& lparam, const double& dparam, const string& sparam)
{
if(id==CHARTEVENT_OBJECT_ENDEDIT && sparam==EDIT_BOX)
{
double value = (double) ObjectGetString(0, EDIT_BOX, OBJPROP_TEXT);
ObjectSetString(0, EDIT_BOX, OBJPROP_TEXT, (string)value);
}
}
You will need a way to validate your input. (an additional button ?)
Keep it simple. Anyway, as you wish :p
You will need a way to validate your input. (an additional button ?)
I'm not sure I follow...?
I may have misunderstood the OP's intention, but I believe the interface will be dynamic i.e. a change in this edit box will result in an update of another box accordingly.
You could have a validation button, but if the result is simply displayed (rather than actioned) it may be an unnecessary addition. But I'm not sure - the OP would need to clarify.
Keep it simple. Anyway, as you wish :p
I very much agree with keeping things simple. Does it get more simple than this?
ObjectSetString(0, EDIT_BOX, OBJPROP_TEXT, (string)value);
PS I'm not sure it is as I wish, it is just an academic discussion for me - I have no need for it!
I'm not sure I follow...?
...If we take it as a general request : "How to check if the content of a variable is numeric ?", the most elegant solution is using regular expression.