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variables holding operators?

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variables holding operators?

Mar 18th, 2007

OK I am wondering Can you make a variable hold an operator.
Such as say +, -, / etc...

And if so can that variable be used to replace an operator in an equation?

for instance

char a = "+";
int b = (2 a 3);

thoguh that doesn't work itself i think it conveys what i am looking for.

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iamthwee

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Re: variables holding operators?

Mar 18th, 2007

No.

What are you trying to do.

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Re: variables holding operators?

Mar 18th, 2007

you can use it in a switch statement

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
int b = 1;
int c = 2;
int d = 0;
switch(a)
{
   case '+':  d = b * c; break;
   case '-':   d = b - c; break;
   case '/':   d = b / c; break;
  // etc
}
int b = 1;
int c = 2;
int d = 0;
switch(a)
{
   case '+':  d = b * c; break;
   case '-':   d = b - c; break;
   case '/':   d = b / c; break;
  // etc
}

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vicky_dev

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Re: variables holding operators?

Mar 18th, 2007

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Originally Posted by JadedTortoise

OK I am wondering Can you make a variable hold an operator.
Such as say +, -, / etc...

And if so can that variable be used to replace an operator in an equation?

for instance

char a = "+";
int b = (2 a 3);

thoguh that doesn't work itself i think it conveys what i am looking for.

You can do this to have the same effect:

 Help with Code Tags 
 c Syntax (Toggle Plain Text) 
#define a +
 
int b = (2 a 3);
#define a +

int b = (2 a 3);

But 'a' is not really a variable here.
And I see no reason why you would want to do that...

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Re: variables holding operators?

Mar 18th, 2007

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Originally Posted by vicky_dev

You can do this to have the same effect:
Help with Code Tags

c Syntax (Toggle Plain Text)
#define a +
 
int b = (2 a 3);
#define a + int b = (2 a 3);
But 'a' is not really a variable here.
And I see no reason why you would want to do that...

You might want to do something like that when writing a calculator. for example, if you enter "2 * 3" then your program needs to figure out what to do.

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Re: variables holding operators?

Mar 18th, 2007

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Originally Posted by Ancient Dragon

You might want to do something like that when writing a calculator. for example, if you enter "2 * 3" then your program needs to figure out what to do.

That is pretty much my reasoning is calculations with the equation from an outside source. I did think of using switches/loops/etc... but they are all rather convoluted ways to do something that would be so simple. Man the more i am learning of C++ the more glaring flaws i am seeing.

Are there any compliers with additions that will fix some things, simple things like length_of(Array), treat_as_value(char). So many things that would make the programing both easier and less taxxing on memory and processor time. And if it was compiled to exe it should retain portability or am i missing something?

I don't know if not is there a langauge I should try that doesn't have such drastic oversights?

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Re: variables holding operators?

Mar 18th, 2007

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Originally Posted by JadedTortoise

Are there any compliers with additions that will fix some things, simple things like length_of(Array), treat_as_value(char).

Not in C or C++ languages.

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Originally Posted by JadedTortoise

So many things that would make the programing both easier and less taxxing on memory and processor time. And if it was compiled to exe it should retain portability or am i missing something?

C/C++ is probably the least taxing of all computer languages except assembly and machine code. Other languages, such as basic, let you do some things a lot easier but the executable programs are generally larger and slower.

If you want to get reall deep into parsing equations then try YACC (Yet Another Compiler Compiler)

Last edited by Ancient Dragon; Mar 18th, 2007 at 3:38 pm.

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