c++ overloading operator>> and operator<< with an arrayclass help please

[wildwolf]

Hello all.

I need help with the implementation of an arrayclass operator overloading.

I have created a class 'arrayclass' but need to overload the operator>> so that I can use:
cin >> myArray[0]; // get input from user and store into index 0 of custom arrayclass.

I also have to have it allow:
cin >> myArray; // allow user to input every index in the class (say...0 to 5)

I can get the "cin >> myArray" to work fine. Where I'm having trouble is implementing the one that allows a specific index of the array to be input. Any clues would be helpful....I'm assuming it'll still use the same instream& return value, but could very well be wrong.

....

Same thing with overloading<< (for cout).
I can implement the "entire array" being output...but not a specific index (although it appears to work w/o overloading it...I'm sure there are cases where it will NEED to be overloaded.

anybody?

 

[Barnaby W. Füi]

myArray[0] is just an expression. It returns whatever arrayclass:perator[](int) returns. THAT is the type you need to be concerned with. As for the actual overloading, I assume you would need to define operator>>(istream, whatever-type-it-is-you're-dealing-with). If it's a built-in type, then it's already taken care of.

 

[wildwolf]

geez...do I feel dumb (for not just trying cin >> myArray[0]; )

I had already wrote the arrayclass:perator[](int) overloaded function....but was assuming (my BIG mistake) that I would need to overwrite the istream & ostream for instances of cin/cout >>/<< myArray[index value] as well.

However, I do have an interesting situation now....

Is there any way to know in the arrayclass:perator[] that the calling function was a cin vs. a cout?
ie if it's a cin, I would like to ignore the newline character from the input....and would need to know if it was a cin in order to do so, correct?

 

[Barnaby W. Füi]

Personally I would probably try to make it so that it either always strips the newline or it never does; I prefer consistency over built-in "intelligence" any day.

You could make two methods, with one ignoring the newline and one not, or a default option, like:

void arrayclass::addText(const std::string& text, bool stripnewline = false)

and then your operator>> could call addText with the second argument set to true. But personally I don't like doing stuff like that, I prefer to avoid options whenever possible, and just provide a clean and straightforward interface to do whatever might be needed. Just kinda depends on the situation.

 

[wildwolf]

Well, I have to strip it, but it has to be selective, I think.

For whatever reason, when I add it to my [] operator overload, it will cause every cout statement to pause between each line...I dunno, I was real tired last night, and will have more time to look more indepthly this afternoon, so perhaps the sleep was the best solution for me.

Btw, thanks for the insight and assistance.