Iterator 사용 방법 예시

#include <iostream>
#include <vector>
 
using namespace std;
 
int main(void)
{
    // vector 값 10개를 추가한다.
    vector<int> vec;
    for (int i = 0; i < 10; i++)
        vec.push_back(i);
 
    // iterator를 이용한 순회
    vector<int>::iterator it;
    for (it = vec.begin(); it != vec.end(); it++)
        cout << *it << endl;
    cout << endl;
 
    // iterator를 포인터처럼 사용할 수 있다.
    it = vec.begin();
    cout << it[3] << endl; // 3
    cout << *(it+3) << endl; // 3
    cout << *(++it) << endl; // 1
    cout << *it++ << endl; // 1
    cout << *it << endl; // 2
 
    it[0] = 100;
    cout << it[0] << endl; // 100
    
    *(it+1) = 200;
    cout << *(it + 1) << endl; // 200
    cout << it[1] << endl; // 200
 
    cout << "--------------------------------------------------" << endl;
    vector<int>::const_iterator cit = vec.begin();
    for (cit = vec.begin(); cit != vec.end(); cit++)
        cout << *cit << endl;
    cout << "--------------------------------------------------" << endl;
    cout << cit[-1] << endl;
    cout << cit[-2] << endl;
    cout << cit[-3] << endl;
    cout << cit[-4] << endl;
    cout << cit[-5] << endl;
    cout << cit[-6] << endl;
    cout << cit[-7] << endl;
    cout << cit[-8] << endl;
    cout << cit[-9] << endl;
    cout << cit[-10] << endl;
    // cout << cit[-11] << endl; // 에러 ㅋ
    cout << "--------------------------------------------------" << endl;
    // vec.begin() 실제 요소, vec.end() 요소가 아님 -> 가리킬 수 없음
 
    // 값이 반전되어 출력함
    vector<int>::reverse_iterator rit;
    for (rit = vec.rbegin(); rit != vec.rend(); rit++)
        cout << *rit << endl;
 
    cout << "--------------------------------------------------" << endl;
    vector<int>::const_reverse_iterator crit;
    for (crit = vec.crbegin(); crit != vec.crend(); crit++)
        cout << *crit << endl;
 
    return 0;
}