C ++“列表迭代器錯誤”

Question

我在以下代碼段中遇到問題。 我已經使用了一段時間，發現問題出現在*pos中。 我只是不確定如何解決它。

#include <iostream>
#include <list>
#include <string>

using namespace std;

list<int>:: iterator pos;           //iterator for pos to allow movement through the list
list<int> numbers;                  // list of int's called "numbers"
int a;                              //  @param a: int to store value at the current position in the list for comparison
int b = 0;                          //  @param b: int to store larger value after comparison



/*function maximum cycles through the list of numbers and assigns the number at each position to variable a
variable a is then compared to variable b which holds the largest element, if variable a is larger than b then
variable a's value is given to b.
*/


int maximum()
{

        for (pos = numbers.begin(); pos != numbers.end(); pos++)
        {
            a = *pos;
                if (a > b)
                {
                    b = a;
                }
        } 

return b; 
}


int main()
{

    int UserNum;        //@param UserNum are the numbers the user will enter that will be added to the list


    //A do loop to fill the list with numbers entered by the user.
    cout << "Enter some numbers (0 to end)" << endl;
    do 
    {
        cin >> UserNum;
        numbers.push_back (UserNum);
    }
    while (UserNum);


    maximum();

    cout << ("Your largest element entered is ") << b << endl;


    system ("PAUSE");

Answer 1

從該行的末尾刪除分號。

 for (pos = numbers.begin(); pos != numbers.end(); pos++) ;

Answer 2

您的for語句結尾處有分號

for (pos = numbers.begin(); pos != numbers.end(); pos++) ;
                                                        ^^^

刪除它，您的代碼應該可以工作。

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編輯：

請注意，如果列表為空，則無法取消對返回的迭代器值的引用，這可能是導致運行時錯誤的原因。 因此，如果您運行代碼並在添加任何數字之前立即輸入0 ，則將收到所看到的錯誤。