Re: [Dev-C++] Operator overloading for built in types.

[Abdelkader G. <go...@li...>]

To have the code presented above compiling, you should try this:
--------------------------------------------------------------
#include <iostream>
#include <stdlib.h>
using namespace std;

//encapsulate the int type inside a
//structure
typedef struct 
{
const int value;
} _int;

//the operator is now defined 
//for the structure _int
bool operator==(const _int i,const _int j)
{
 cout << "hello" <<endl;
 return (i.value + j.value);
}


int main(int argc, char *argv[])
{
  _int i = {1};
  _int j = {-1};
  cout << (i == j) <<endl;
  return 0;
}
---------------------------------------------------

The output is:
hello
0

kind regards,


> hi there,
> 
> Are you sure that you can overload operator for simple types that are
> not  classes? You can emulate built in types operators for you 
> defined 'classes', but I'm not sure that you can redefine operator for 
> built in types and if this is allowed what a catastrophy it would be ,)
> imagine this (bogus) code:
> 
> bool operator==(const int i,const int j)
> {
>  return (bool) (i + j);
> }
> //this code change the semantics of ==
> // 4 == -4 -> true 4 == 4 ->false
> 
> If you are allowed to change the definition of the == (int equals) this
> means that this operator is changed for 'all' int == operation, so can
> you  imagine what happends if you include others source code that have
> used  another semantics for the (int ==).
> 
> So, I'm not sure that you can overload built in types but if you have
> more  information I'm interested ,)
> 
> Kind regards;   
> 
>> Ok here is my dilema.
>> 
>> Scattered throught my code is the following line:
>> 
>> if(!strcmp(var1,var2))
>> ....
>> 
>> What would be the best way to change that to
>> 
>> if( var1 == var2 )
>> ....
>> 
>> So far here is some exaple code that illustrates my problem:
>> bool operator==(char *s1, char *s2)
>> {
>>   if(!strcmp(s1,s2))
>>     return true;
>>   else
>>     return false;
>> }
>> 
>> int main()
>> { 
>>   char x[10] = "Hello";
>>   char y[10] = "Hello";
>>   if(x == y)
>>     cout << "Equal" << endl;
>>   else
>>     cout << "Not equal" << endl;
>>   cin.get();
>>   return 0;
>> }
>> 
>> Error:
>> C:/Documents and Settings/David/My Documents/scratch.cpp:9: `bool 
>>    operator==(char*, char*)' must have an argument of class or
>> enumerated type
>> 
>> What does it mean?? I have done operator overloading with various
>> classes but I can't get it to work with char *, please help. There is
>> no one to make it a friend with so that is ruled out.
>> 
>> =====
>> Signed 
>> David Mcken
>> 
>> Life Sucks
>> Live with it
>> 
>> __________________________________
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>> 
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> 
> 
> 
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