尝试使用const_iterators时出现运行时错误。错误是:列出迭代器而不是dereferencable。我知道const_iterator不能被解引用来为列表赋值,但是我试图取消引用迭代器来访问列表中的值。我正在使用Visual Studio 2010专业版。
我已经对此进行了相当多的研究,但没有找到任何可以帮助我理解我做错的事情。
#include <list>
#include <iostream>
using namespace std;
template <typename T>
list<T> interleaveLists(const list<T>& l, const list<T>& m)
{
list<T> interleavedList;
list<T>::const_iterator iter1;
list<T>::const_iterator iter2;
list<T>::const_iterator iter3;
list<T>::const_iterator iter4;
iter1 = l.begin();
iter2 = l.end();
iter3 = m.begin();
iter4 = m.end();
while (iter1 != iter2 || iter3 !=iter4)
{
interleavedList.push_back(*iter1);
interleavedList.push_back(*iter3);
iter1++;
iter3++;
if (iter1 == iter2)
{
interleavedList.push_back(*iter3);
}
if (iter3 == iter4)
{
interleavedList.push_back(*iter1);
}
} // end while
return interleavedList;
} //end interleaveLists
//******************************************************************
int main()
{
list<int> list1;
list<int> list2;
list<int> list3;
list<int> newList;
// Create list1 = {40, -5, 66, -7, 8}
list1.push_back(40);
list1.push_back(-5);
list1.push_back(66);
list1.push_back(-7);
list1.push_back(8);
// Create list2 = {22, 3, -4}
list2.push_back(22);
list2.push_back(3);
list2.push_back(-4);
newList = interleaveLists(list1, list2);
while (!newList.empty())
{
cout << newList.front() << " ";
newList.pop_front();
}
cout << endl;
newList = interleaveLists(list3, list2);
while (!newList.empty())
{
cout << newList.front() << " ";
newList.pop_front();
}
cout << endl;
} // end main
答案 0 :(得分:2)
您可以循环超出范围。如果iter1 == iter2,但是iter3!= iter4,则下面的代码将是push_back(* iter1),尽管iter1已经是l.end()。
while (iter1 != iter2 || iter3 !=iter4)
{
interleavedList.push_back(*iter1);
interleavedList.push_back(*iter3);
答案 1 :(得分:0)
您尝试取消引用等于end()的迭代器的问题。
while (iter1 != iter2 || iter3 !=iter4)
{
interleavedList.push_back(*iter1); // here is invalid code
interleavedList.push_back(*iter3); // here is invalid code
iter1++; // here is invalid code
iter3++; // here is invalid code