Chapter. 6

마구잡이 실습하기

#include <iostream> #include <algorithm> #include <vector> #include <iterator> #include <numeric> using namespace std; class Num { private: int m_num; public: Num() { m_num=0; } Num(int n) : m_num(n) {} Num operator+(const Num& n) { return Num(m_num + n.m_num); } Num& operator=(const Num& n) { m_num = n.m_num; return *this; } int getNum() const { return m_num; } friend ostream& operator<<(ostream& o, const Num& n); }; inline bool IsOdd (int i) { return ((i%2)==1); } inline bool IsEven(int i) { return ((i%2)==0);} inline ostream& operator<<(ostream& o, const Num& n) { o << n.m_num; return o; } inline bool isNumEven(const Num& n) { return n.getNum() % 2 == 0; } inline Num tenTime(const Num& n) { return Num(n.getNum() * 10); } int main () { // ref : http://www.cplusplus.com/reference/algorithm/remove_copy_if/ int myints[] = { 1,2,3,4,5,6,7,8,9 }; vector<int> vec(9); vector<int> myvector (9); vector<int>::iterator it; copy(myints, myints+9, vec.begin()); remove_copy_if(vec.begin(), vec.end(), myvector.begin(), IsOdd); cout << "\n<vec contains>\n"; copy( vec.begin(), vec.end(), ostream_iterator<int>(cout, " ") ); cout << "\n<myvector contains>\n"; copy( myvector.begin(), myvector.end(), ostream_iterator<int>(cout, " ") ); /* it = remove_if(vec.begin(), vec.end(), IsEven); cout << "<vec contains after remove_if()>\n"; copy( vec.begin(), vec.end(), ostream_iterator<int>(cout, " ") ); vec.erase(it, vec.end()); cout << "<vec contains after erase()>\n"; copy( vec.begin(), vec.end(), ostream_iterator<int>(cout, " ") ); */ it = stable_partition(vec.begin(), vec.end(), IsOdd); cout << "\n<vec contains after stable_partition()>\n"; copy( vec.begin(), vec.end(), ostream_iterator<int>(cout, " ") ); cout << "\n<Invalidation of iterator of vector>\n"; it = vec.begin(); cout << *it << endl; vec.insert(vec.begin()+2, 999); cout << *it << endl; cout << "\n<vec contains after insert()>\n"; copy( vec.begin(), vec.end(), ostream_iterator<int>(cout, " ") ); vector<Num> numVec; for (vector<Num>::size_type i=0 ; i<10 ; ++i) { numVec.push_back(Num(i+1)); } Num accNum = accumulate(numVec.begin(), numVec.end(), Num(0)); cout << "\n<numVec contains>\n"; copy( numVec.begin(), numVec.end(), ostream_iterator<Num>(cout, ", ") ); cout << "\n<result of accumulate()>\n"; cout << accNum << endl; stable_partition(numVec.begin(), numVec.end(), isNumEven); cout << "\n<numVec contains after stable_partition>\n"; copy( numVec.begin(), numVec.end(), ostream_iterator<Num>(cout, ", ") ); transform(numVec.begin(), numVec.end(), numVec.begin(),tenTime); cout << "\n<numVec contains after transform>\n"; copy( numVec.begin(), numVec.end(), ostream_iterator<Num>(cout, ", ") ); vector<int> u(10, 100); vector<int> v; copy(u.begin(), u.end(), back_inserter(v.begin())); cout << "\n<v contains>\n"; copy( v.begin(), v.end(), ostream_iterator<Num>(cout, ", ") ); return 0; }



- 주의!

// src와 dest는 벡터 또는 리스트 등 copy(src.begin(), src.end(), dest); // 컴파일러 에러 copy(src.begin(), src.end(), dest.begin()); // dest가 비어 있으면 런타임 에러! copy(src.begin(), src.end(), dest.end()); // dest.end()는 어떤 요소를 가리키고 있지 않다. // 런타임 에러! copy(src.begin(), src.end(), dest.end()-1); // 이런식으로도 안 된다. 런타임 에러! copy(src.begin(), src.end(), back_inserter(dest)); // 된다. dest의 뒤에 src를 복사한다. copy(src.begin(), src.end(), front_inserter(dest)); // 된다. dest의 앞에 src를 복사한다.