C++ part B 第一周 （上）

the enum of C++ 11 have some new features

enum class WierdLogic :unsigned{NO, MAYBE = 5, YES = 10}; 

<regex> - regular expression

<thread> - threading

<unordered_map> - hash based map

<array> - fixed size array

<forward_list> - singly linked list

And much more...

In C

C container is an array such as: int d[100]

C iterator is a pointer : int *p = d;

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C algorithm is : rand(), sqrt() ...

Generics can be done clumsily with void*

We have seen input and output iterators

Must have a single pass algorithm such as find

Next up forward, bidirectional,random access

Search forward direction one-by-one.

The operator ++ is defined("advance the iterator") and dereferencing operators * and ->.

Iterators may be compared for equality == and != and may be constructed and copy constructed.A canonical algorithm using this iterator is the STL replace algorithm:

template<class T>
  void replace(ForwardIterator first, ForwardIterator last, const T&x, const T&y); 

This algorithm replaces occurences of x by y in the specified iterator range.

#include <iostream>
#include <iterator>
#include <fstream>
#include <vector>

using namespace std;

template<typename ForwardIterator> 
void square(ForwardIterator first, ForwardIterator last){
    for(; first!=last; first++)
    *first = (*first)*(*first);
}

int main(){
    vector<int> w = {1,2,3,4,5};
    square(w.begin(), w.end());
    for(auto i:w)
    cout << i << "\t";
    cout << endl;
}