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Mar 18th, 2007

variables holding operators?

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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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JadedTortoise

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Mar 18th, 2007

Re: variables holding operators?

No.

What are you trying to do.

iamthwee

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Mar 18th, 2007

Re: variables holding operators?

you can use it in a switch statement

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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Mar 18th, 2007

Re: variables holding operators?

Click to Expand / Collapse Quote 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:

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...

vicky_dev

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Mar 18th, 2007

Re: variables holding operators?

Click to Expand / Collapse Quote originally posted by vicky_dev ...

You can do this to have the same effect:
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?

Click to Expand / Collapse Quote 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?

JadedTortoise

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Mar 18th, 2007

Re: variables holding operators?

Click to Expand / Collapse Quote 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.

Click to Expand / Collapse Quote 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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