Question

所以我正在为数据库存储编写程序，第一步是将信息从文本文件加载到struct数组。但是，在读/写过程中我收到一条错误消息，说该程序进入超出范围的实例。

while (!inFile.eof())
{
    getline(inFile, dataLine);              //saves the line of the file into a string

    a[i].name = dataLine.substr(0, 17); // 18
    a[i].author = dataLine.substr(19, 33); // 15
    a[i].vol = dataLine.substr(35, 60); // 26
    a[i].pub = dataLine.substr(62, 77); // 16
    a[i].year = dataLine.substr(79, 82); // 4
    a[i].price = dataLine.substr(84, 91); // 8
    a[i].copies = dataLine.substr(93, 96); // 3


    i++;    //moves through the array after each line.
    count++;    //counts how many lines/items there are in the file entered for the program
}

我已将问题缩小到本节，但我似乎无法弄清楚是什么导致它出错。

terminate called after throwing an instance of 'std::out_of_range'
what():  basic_string::substr: __pos (which is 19) > this->size() (which is 0)
Aborted

这是我收到的错误消息。

Answer 1

您面临的具体错误是dataLine的长度为零，并且您正尝试子串。此处描述了异常：http://www.cplusplus.com/reference/string/string/substr/

对字符串的长度进行额外检查可以解决此问题。

if (dataLine.size() >= 97) {
    ...
}

读取结构数组时超出范围错误

1 个答案: