Question

我正在编写一个代码来获取一行中的单词。由于我无法获得任何直接功能，这就是我编写的代码。我需要在我的主程序中一次又一次地调用它，因此我已经使它成为一个函数。但是，每当我在主循环中调用它时，它表示变量b未初始化。任何帮助都非常感谢。 TIA！

vector <string> output_words(string stri) //FUNCTION TO GET INDIVIDUAL WORDS FROM A LINE 
{
    vector <string> substring; // Contains words from single lines
    vector <string> output1;


    int b;

    //create variables that will act as "cursors". output words between them.
    size_t pos1 = 0;
    size_t pos2;

    string str;// = "Hello My Nme is Ruth";




    int a = str.length(); // abc[i] is a string in the vector, NOT THE VECTOR!

    for (int x = 0; x < a; x++)
    {
        pos2 = str.find(" ", pos1);
        //substring.resize(i);
        substring.resize(a); // Need to resize a vector so never points to zero
        substring[x] = str.substr(pos1, (pos2 - pos1));
        substring.push_back(substring[x]);
        //std::cout << "pos1:" << pos1 << ", pos2:" << pos2 << std::endl;
        pos1 = pos2 + 1; // sets pos1 to the next character after pos2. 
                         //so, it can start searching the next " ".
        if (x > 0)
        {
            if (substring[0] == substring[x])
            {
                substring.erase(substring.begin() + x);
                //one_string.erase(one_string.end());
                b = x;
                goto label;
            }
        }
    }


label: for (int i = 0; i < b; i++)
    {
        output1.resize(b);
        output1[i] = substring[i];

    }

    return output1;
}

Answer 1

您没有将变量int b;设置为任何内容，它实际上是未初始化的。您所要做的就是将b设置为某个（通常为0）。

Answer 2

您尚未更新b的值。你刚刚在第6行声明了变量b而没有初始化。所以请将它初始化为适当的值。

Answer 3

由于您尝试在b内分配for { if { if { /* * */ } } }，因此可能未分配任何值（如果不满足某些条件）。如果发生这种情况，则label: for (int i = 0; i < b; i++)会尝试访问未初始化的b，这会导致undefined behavior。

运行时错误，变量b未初始化

3 个答案: