Help with creating arrays? | SoloLearn: Learn to code for FREE!

0

Help with creating arrays?

https://code.sololearn.com/cC6LlNe7zCvi/?ref=app In my class Array, I want to overload the []-operator so that I can not only get a value, but also use it to assign a value to the array. My idea was that I need a function to return a pointer to the array/to the position in the array I want to assign the value to. Am I right on this and just failed to execute it? Or is my assumption completely wrong and I need a different view on the problem? A detailed explanation is deeply appreciated!

12/1/2017 1:15:30 PM

Shadow

2 Answers

New Answer

+2

I assume you want to do something like arr[0] = 5; arr[1] = 3; etc... The operator[] should return a reference, not a copy. A& operator[](int pos) { return myArray[pos]; } The reason for this is that if you don't use a reference and return a copy instead you return an rvalue, rvalues cannot be assigned anything. For example if you return 5 and want to assign 3 to it you are basically saying 5 = 3, which makes no sense. If you return a reference you return an lvalue, which can be modified. Some_address_in_memory = 3, this of course does make sense. Lastly there should also be a const version for the operator[] const A& operator[](int pos) const { return myArray[pos]; } Random tips: You should use std::size_t for indexes, not an int, because an int can represent negatives and negative indexes for an array make no sense either ^^. Don't forget delete in the destructor, since you used a new. Inside the string function: void operator=(std::string s) { this->str = s; } should return a reference to itself, this is to allow chaining. ( return *this; ) e.g. a = b = c = d; Also you probably want to take std::string as a const reference too.

0

Thank you so much for helping me out with this code again! Now that you explained things they seem so obvious to me... Im always mad if I cant solve things on my own, but I guess sometimes asking others is really the only way^^.