Von C++ CopyConstructor ausgelöste Ausnahme! !

Question

Der Code lautet wie folgt:

void CopyStr(char *&destination, char *&source) {
    int sz = strlen(source) + 1;//此处引发异常！！
    destination = new char[sz];
    for (unsigned i = 0; source[i] != 'Rrreee'; i++)
        destination[i] = source[i];
    destination[sz - 1] = 'Rrreee';
    return;
}

Data::Data(Data &adata) {
    CopyStr(adata.P_name, P_name);
    CopyStr(adata.address, address);
    CopyStr(adata.number, number);
}

Codebeschreibung: Die Datenklasse hat jetzt drei char*-Mitglieder, nämlich P_name, Adresse und Nummer.

Zusammengestellte Bilder:

Bitte gib mir die Antwort, danke! !

Answer 1

首先char *&source这种参数改为char *const &source，其次CopyStr(adata.P_name, P_name),这种改为CopyStr(P_name, adata.P_name)。
这是我测试的代码，直接可以运行：

#include <iostream>
#include <cstring>
using std::cout;
using std::endl;
using std::strlen;
class Data
{
public:
  char *a = "";
  char *b = "";
  char *c = "";
  Data(char *a, char *b, char *c):a(a),b(b),c(c) {};
  Data(Data const &data);
};


int CopyStr(char * &des,  char *  const &source)
{
  int sz = strlen(source) + 1;
  des = new char(sz);
  for (unsigned i = 0; source[i] != '\0'; i++)
    *(des +i)  = source[i];
  *(des+sz - 1) = '\0';
  return 0;
}

Data::Data(Data const  &data)
{ 
  CopyStr(a, data.a);
  CopyStr(b, data.b);
  CopyStr(c, data.c);
}

int main()
{
  Data data = Data("abcd", "b", "c");
  char * p = "232323";
  Data data2 =  Data(data);
  char * p2 = "1232";
  CopyStr(p2, p);
  cout << p2 << endl;
  cout << data.a << endl;
  cout << data2.a << endl;
  return 0;
}

Answer 2

调用CopyStr时的第二个参数（比如P_name）是哪里来的？

Answer 3

vs会用0xCCCCCCCC填充未初始化的内存区域（这也是烫烫烫的由来）；
考虑到你访问到了0xCCCCCCCC，所以要不就是你传进去了个非法指针，要不就是这个char*指针对应的字符串没有以'0'结尾；
可以试着输出一下source的值，然后逐字节输出指针所指向的数据试试