【问题标题】：Receiving an exception in overloaded operator >> section在重载的运算符 >> 部分中接收异常
【发布时间】：2020-01-10 06:11:38
【问题描述】：

所以我为 MyString 类重载了一个运算符“>>”。它应该从文本文件中读取信息到自定义字符串，但是当我尝试按字符填充字符串时出现异常。 Text.txt 仅包含“xyz”

Main.cpp：

#include "MyString.h"
#include <fstream>
#include <iostream>
//TO-DO 1 CharArr for all
int main() {

    MyString NewString;
    ifstream In("Text.txt");
    In >> NewString;

    cout << NewString << endl;
    system("pause");
    return 0;
}

构造函数：

MyString::MyString() {
    StringLength = 0;
    Pointer = nullptr;
}

MyString::MyString(const char* String) {
    for (int i = 0; String[i]; i++)
    StringLength++;
    Pointer = new char[StringLength + 1];
    char *Source = (char *)String;
    char *Destination = (char *)Pointer;
    for (int i = 0; i < StringLength + 1; i++)
    Destination[i] = Source[i];
}

操作员：

istream &operator>>(istream &In, MyString &String) {
    int FileStringLength = 0;
    char Character;
    if (String.Pointer != nullptr)
        delete[] String.Pointer;
    while (In.get(Character) && Character != '\n')
        FileStringLength++;
    if (FileStringLength < 1000 && FileStringLength != 0) {
        String.StringLength = FileStringLength;
        In.clear(), In.seekg(0, ios::beg);
        for (int i = 0; In.get(Character) && Character != '\n'; i++)
                String.Pointer[i] = Character; // I get an exception here
    }
    else if (!FileStringLength) {
        cout << "File is empty." << endl;
    }
    else {
        cout << "File contains too many characters." << endl;
    }

    return In;
};

【问题讨论】：

delete 之后哪里有空间放Character？

标签： c++ ios class overloading operator-keyword

【解决方案1】：

if (String.Pointer != nullptr)
    delete[] String.Pointer;

释放存储空间

String.Pointer[i] = Character; // I get an exception here

打算用。

解决方案：

不要delete[] 存储。而是重写它直到存储空间已满，然后分配一个新的更大的缓冲区用于存储，将旧缓冲区复制到新缓冲区中，然后释放旧缓冲区。

【讨论】：