Help me

My all msg got cleared?? WoW

Hi everyone

What's comp for in `template ForwardIterator max_element (ForwardIterator first, ForwardIterator last, Compare comp);`?

comp is a comparator functor. Basically a "function" that compares two elements. The difference with using a function overload without comparator that it will use default operator < (less than). There can be cases when: - there's no such operator - there is such an operator, but you want to find "max element" by some other crieria (for example your "less than" operator compares ID field of your structure, but you want to find a structure with maximum Age field).

so a max_element() with a comparator a<b and without a comparator are equivalent?

They are equivalent only if your comparator have the same logic as operator<

ok so that way i can customise it to return the min element of an array of ints by changing the comparator to a>b?

They are equivalent only if your comparator have the same logic as operator<

also, what does the meaning < hold there, if they are equivalent?

also, what does the meaning < hold there, if they are equivalent?

Well, comparison operators can be used for many things (e.g. using containers such a std::map)

I guess, for a map it decides how the elements are stored in red-black tree?

I guess, for a map it decides how the elements are stored in red-black tree?

Yes, you need to be able to correctly tell whether one element is less than another to be able to build a correct binary tree (not only red-black)

What's the intuition behind using < as the comparator in case of the max_element function? or is that i should just remember that < helps in finding the max element and hence > will help in finding the min element

Nope, I might said it in an incorrect way. You define your operator< as well with other operators to be able to compare them. When you do you don't think much about the algorithms that you will use on them, just that they should be compared in some predictable manner that makes sense for this type. Then, when you use an algorithm like max_element, you either go along with your default operator< if it's what you need, or you use that version with comp that we've started from. In the second case you use that comparator to achieve the behavior that you need from the algorithm.

asking about the second case, i wanted to ask that how does comparator uses < help in finding the max_element.

You can note in the Possible Implementation section how they can use it. https://en.cppreference.com/w/cpp/algorithm/max_element

big, thanks for that. it helped me the understand implementation

You can note in the Possible Implementation section how they can use it. https://en.cppreference.com/w/cpp/algorithm/max_element

BTW, these implementation depend upon which factors?

Developers of specific compilers may use different implementations (for example if they find a more efficient way to implement that algorithm)

https://stackoverflow.com/questions/10476665/avoiding-copy-of-objects-with-the-return-statement

#include <iostream> struct A { int a; int b; int c; int d; }; A create(int i) { A a = {i, i+1, i+2, i+3 }; std::cout << &a << "\n"; return a; } int main(int argc, char*[]) { A a = create(argc); std::cout << &a << "\n"; }

Yes.

https://brechtsanders.github.io/xlsxio/

too late

Fucking God, u have a good laptop and using the shit like codeblocks or something else. Is it so hard in install something normal?

It's turbo c++...for some reason indian schools and colleges make us use these

U have ur own head.

Don't make ur life more difficult with the shit from the past times).

you* your*

Lol which Indian uni is forcing u to use turbo C++ ???

Nah, make it in Visual Studio or CLion/Qt Creator for Linux.

I use visual studio ....i am just telling !!