容器迭代器

容器迭代器

iterator：普通正向迭代器

• 可以读取

• 可以修改

  int main()
  {vector<int> vec;for (int i = 0; i < 20; i++){vec.push_back(rand() % 100 + 1);}auto it = vec.begin();for ( ;it != vec.end();it++ ){if (*it % 2 == 0){*it = 0;}}for (int val : vec)cout << val << " ";cout << endl;return 0;
  }
  

const_iterator:常量迭代器

const_iterator 继承自iterator

• 只读

• 不写

  int main()
  {vector<int> vec;for (int i = 0; i < 20; i++){vec.push_back(rand() % 100 + 1);}vector<int>::const_iterator it = vec.begin();for ( ;it != vec.end();it++ ){if (*it % 2 == 0){cout << *it << " ";}     }cout << endl;return 0;
  }

reverse_iterator 反向迭代器

反向遍历容器的元素

int main()
{vector<int> vec;for (int i = 0; i < 20; i++){vec.push_back(rand() % 100 + 1);}vector<int>::const_iterator it = vec.begin();for ( ;it != vec.end();it++ ){cout << *it << " ";     }cout << endl;vector<int>::reverse_iterator rit = vec.rbegin();for (; rit != vec.rend(); rit++){cout << *rit << " ";}cout << endl;return 0;
}

const_reverse_iterator 常量反向迭代器

• 反向遍历
• 只支持读，不能写