C++ 当使用向量大小作为while循环的标准时，如何防止调试ERORR？

我创建了一个程序，可以将2到100之间的所有整数的向量（numberset）转换为该向量中的素数列表。它是通过从向量中移除数字来实现的，如果这些数字可以被除自身之外的一系列数字整除

我很难让这段代码在没有调试错误的情况下运行，最终确定问题与使用向量的大小作为while循环条件的一部分有关。因为从向量中删除数字也会减少向量的大小，所以我的循环变量（j）可能会“跳过”向量中的条目——可能会导致它尝试访问不存在的向量大小

我找到的解决方案是，每当我减少向量大小时，将循环变量减少1。然而，我想知道是否有其他方法可以解决这个问题。谢谢大家!

#include <iostream>
#include "../../std_lib_facilities.h" // available at http://www.stroustrup.com/Programming/std_lib_facilities.h
#include <vector>

vector<int> numberset;
int j = 0;
int main()
{

    bool primetest = true;
    // Adding numbers to our list of potential primes (excluding the number 1)
    for (int i = 2; i <= 100; i++)
    {
        numberset.push_back(i);
    }

    // j represents the current position within the vector numberset
    while (j <= numberset.size()-1)

        // We're going to look through all the numbers in the vector above, and then divide them by a set of divisors to verify that they're prime. Numbers in the above set that are divisible by a divisor will be removed, since they are not prime.
        {
        for (int divisor = 2; divisor <= 100; divisor++)
            // These are the numbers by which we will divide the vectors
        {
            //If a certain number within the vector (marked by position j) can be divided a different number >= 2 with a remainder of 0, we know it's not prime.
            //We will then set the 'primetest' bool to "false" (indicating that we know this is not a prime number)

            if (numberset[j] % divisor == 0 && numberset[j] != divisor)

            {
                primetest = false;
                if (primetest == false)
                {
                    //This line removes the non-prime number from our list of numbers.
                    numberset.erase(numberset.begin() + j);
                    //j-- is added in to prevent the code from 'skipping' over numbers in the numberset vector after a number within the vector is removed. 
                    //For example, let's say the third element in the vector (numberset[3]) is 6. If we remove 6 (since it's not prime), the third element then becomes 7, and the 4th element becomes 8. 
                    //However, the j++ below will cause us to next review (numberset[4]), which is 8 rather than 7. Thus the addition of j--, which cancels out the j++ and makes sure we're not skipping elements.
                    //j++ only runs if a number is erased from the vector, however.
                    j--;
                    }
            }
        }
        j++;


    }

    //This prints out the remaining prime numbers in the vector.
    for (int x : numberset)
    {
        cout << x << " ";

    }


}

#包括
#包括“./../std_lib_facilities.h”//可在http://www.stroustrup.com/Programming/std_lib_facilities.h
#包括
向量集；
int j=0；
int main（）
{
bool-primetest=true；
//向我们的潜在素数列表中添加数字（不包括数字1）
对于（int i=2；i）您会得到什么运行时错误？
而（j）在您将其切换为
size\u类型之后，请注意，这是一个无符号数字，如果您尝试从0中减去1，它将下溢。不确定这会如何更改您的算法（我假设这是您现在的问题），但您需要注意。我通过不改变我正在迭代的容器（而是使用单独的结果容器，并且可能在完成时与原始容器交换
std:：swap
）或者使用@RemyLebeau关于不需要if（primetest==false）的优点来解决这类问题条件；我删除了它。我发现将numberset.size（）-1更改为numberset.size（）会导致调试错误。如果没有-1，代码不会尝试访问向量中超出向量范围的元素吗？用break替换j--会导致代码生成2加上从3到99的所有奇数。