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Niqq's questions

Martin Hope
Niqq
Asked: 2025-03-05 21:46:02 +0000 UTC
  • 4
#include <iostream>

struct String
{
public:
  String();
  String(const char *str);
  String(const String& str);
  void print();
  ~String();
  String& operator=(const String& other);
  String operator+(const String& other);

private:
  char *str;
  int lenght;
};

String::String()
{
  this->str = nullptr;
  lenght = 0;
}

String::String(const char *str)
{
  lenght = strlen(str);
  this->str = new char[lenght + 1];

  for(int i = 0; i < lenght; i++)
  {
    this->str[i] = str[i];
  }
  this->str[lenght] = '\0';
}

String::String(const String& other)
{
  
  lenght = other.lenght;
  this->str = new char[lenght + 1];
  for (int i = 0; i < lenght; i++)
  {
    this->str[i] = other.str[i];
  }
  this->str[other.lenght] = '\0';
}

void String::print()
{
  std::cout << str;
}



String::~String()
{
  delete[] this->str;
  this->str = nullptr;
}

String& String::operator=(const String& other)
{
  if (this->str != nullptr)
  {
    delete[] str;
    str = nullptr;
  }

  lenght = other.lenght;
  this->str = new char[lenght + 1];
  for (int i = 0; i < lenght; i++)
  {
    this->str[i] = other.str[i];
  }
  this->str[other.lenght] = '\0';

  return *this;
}

String String::operator+(const String& other)
{

  String NewStr;
  NewStr.lenght = this->lenght + other.lenght;
  NewStr.str  = new char[NewStr.lenght + 1];
  
  int i = 0;
  for (;i < this->lenght; i++)
  {
    NewStr.str[i] = this->str[i];
  }
  for (int j = 0; j < other.lenght; j++, i++)
  {
    NewStr.str[i] = other.str[j];//предупреждение в этой строке
  }
  NewStr.str[NewStr.lenght] = '\0';
  

  return NewStr;
}

int main()
{
  String a("Hello");
  String b("lello");
  String c;
  c = a + b;


  c.print();
}

更换时

NewStr.lenght = this->lenght + other.lenght;
      NewStr.str  = new char[NewStr.lenght + 1];

在

NewStr.lenght = this->lenght + other.lenght;
      NewStr.str  = new char[this->lenght + other.lenght + 1];

警告消失

c++