Operator overload in c++ class

Question

Trying to overload the < and > operators in a c++ class

 template <typename T> bool BinaryTree<T>::operator < (BinaryTree<T> &B) { return (this->count < B.setCount(0)); } template <typename T> float BinaryTree<T>::setCount(float c) { count += c; return count; }

Where setCount(0) returns the count of the B obj. But this always outputs true no matter the numbers compared.

Changes my code to

template <typename T> bool BinaryTree<T>::operator < (const BinaryTree<T> &B) { return (this->count < B.count); } printf("%c %lf\n", tree[0]->getData(), tree[0]->setCount(0)); printf("%c %lf\n", tree[1]->getData(), tree[1]->setCount(0)); Output > a 0.750000 b 0.250000 if(tree[0] < tree[1]) printf("0 < 1\n"); else printf("1 > 0\n"); Output > 0 < 1

(Should probably be taking a const&.) What does your debugger tell you about the two values you're comparing when you run that code? — Mat
– Mat, Commented May 1, 2012 at 8:35
Are you sure it's B.setCount() you need to compare to? My gut feeling tells me you want to compare to B.count! Oh, and it doesn't matter if count is private. — Mr Lister
– Mr Lister, Commented May 1, 2012 at 8:38
Try and print the value of ` B.setCount(0)` and this->count and manually check if its a flaw or something true . May be the condition is always true and you have not implemented setCount function correctly — Invictus
– Invictus, Commented May 1, 2012 at 8:38
setCount() is correct, printf doesn't work in the operator method — andrei
– andrei, Commented May 1, 2012 at 8:39

juanchopanza · Accepted Answer · 2012-05-01 09:11:35Z

This:

 printf("%c %lf\n", tree[0]->getData(), tree[0]->setCount(0)); printf("%c %lf\n", tree[1]->getData(), tree[1]->setCount(0));

suggests to me that tree holds pointers to your BinaryTree<T>.

Here, you are comparing pointers, i.e memory addresses, not values:

if(tree[0] < tree[1]) printf("0 < 1\n"); else printf("1 > 0\n");

You probably need

if(*(tree[0]) < *(tree[1])) printf("0 < 1\n"); else printf("1 > 0\n");

Very good. I missed that; did have an idea that he might not be calling his defined operator<, but I was not sure why that might happen. This explains it.

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