使用对象时内存泄漏,C\C++交流,技术交流,鱼C论坛

沐丶心 发表于 2021-4-14 14:40:17

使用对象时内存泄漏

本帖最后由沐丶心于 2021-4-14 14:43 编辑

头文件
#ifndef SHOOK_
#define SHOOK_
#include <iostream>
class string2
{
private:
   char * str;
   int len;

public:
   //初始化部分
   string2();
   string2(const char* c);
   string2(const string2 &c);
   ~string2();
   string2 & operator=(const string2 &c);
   //功能
   int has(const char ch);//返回ch在str中出现的次数
   void stringup();
   void stringlow();
   //重载运算符
   friend string2 operator+(const string2 &b,const string2 &c);//要返回一个对象。调用复制构造函数
   friendbooloperator==( const string2 &b,const string2 &c);
   friendstd::ostream & operator<<(std::ostream & os,const string2 &c);
   friendstd::istream & operator>>(std::istream & os, string2 &c);
};
#endif
类定义
#include <iostream>
#include "string2.h"
#include <cctype>
string2::string2()
{
str = new char;
str='\0';
}
string2::string2(const char* c)
{
len = strlen(c);
str = new char;
strcpy(str,c);

}
string2::string2(const string2 &c)
{
len = strlen(c.str);
str = new char;
strcpy(str,c.str);
}
string2::~string2()
{
std::cout<<"/"<<str<<"/"<<std::endl;       ---------------------------------标记被删除的对象
delete []str;

}

int string2::has(const char ch)
{
int count = 0;
while(*str++ !='\0')
   if(*str==ch)
         count++;


return count;
}
void string2::stringup()
{
for(int i=0;i<len;i++)
   if(islower(str))
         str=str-32;
}
void string2::stringlow()
{
for(int i=0;i<len;i++)
   if(isupper(str))
         str=str+32;
}
string2 & string2::operator=(const string2 &c)
{
if(this == &c)
   return *this;
delete []str;
len = strlen(c.str);
str = new char;
strcpy(str,c.str);
return *this;
}
string2 operator+(const string2 &b,const string2 &c)
{
string2 s;
s.len = b.len +c.len;
s.str = new char;//给出充足地址；
strcpy(s.str, b.str);
strcat(s.str, c.str);
return s;
}
bool operator==(const string2 &b,const string2 &c)
{
return (std::strcmp(b.str,c.str)==0);
}
std::ostream& operator<<(std::ostream &os,const string2 &c)
{
os <<c.str<<std::endl;
return os;
}
std::istream & operator>>(std::istream & is, string2 & c)
{
char temp;
is.get(temp, 20);
if (is)
c = temp;
while (is && is.get() != '\n')
continue;          //删除多余的字符
return is;
}

使用类
#include <iostream>
using namespace std;
#include "string2.h"
int main()
{
string2 s1(" and I am a C++ student. ");
string2 s2= "Please enter your name: ";
string2 s3;
cout << s2;
cin >>s3;
s2 = "My name is "+s3;
cout<<s2<<std::endl;
s2=s2 +s1;
s2.stringup();
cout<<"The string\n"<<s2<<"\ncontains "<<s2.has('A')<<" 'A' characters in it.\n";
s1= "red";
string2 rgb={string2(s1),string2("green"),string2("blue")};
cout<<"Enter the name of a primary color for mixing light: ";
string2 ans;
bool success = false;
while(cin>>ans)
{
   ans.stringlow();
   for(int i =0;i<3;i++)
   {
         if(ans==rgb)
         {
            cout<<"That's right!\n";
            success =true;
            break;
         }
   }
   if(success)
         break;
   else
   {
         cout<<"Try again1\n";
   }
   cout<<"Bye\n";
   return 0;
}

}
运行结果
Please enter your name:
xiaoming
/xiaoming/
/My name is xiaoming/
/My name is /
My name is xiaoming

/My name is xiaoming and I am a C++ student. /
The string
MY NAME IS XIAOMING AND I AM A C++ STUDENT.

contains 5 'A' characters in it.
/red/
Enter the name of a primary color for mixing light: black
/black/
Try again1
Bye
/black/
/blue/
/green/
/red/
/xiaoming/
//----------------------貌似丢失了两个？？？
pe12_2(19954,0x102c07d40) malloc: *** error for object 0x15270414d: pointer being freed was not allocated
pe12_2(19954,0x102c07d40) malloc: *** set a breakpoint in malloc_error_break to debug
zsh: abort    ./pe12_2

是定义时语法问题吗。已经找了好几遍，还是不行啊{:10_250:}
求解答

人造人 发表于 2021-4-14 17:38:59

#ifndef SHOOK_
#define SHOOK_
#include <iostream>
class string2
{
private:
char * str;
int len;

public:
//初始化部分
string2();
string2(const char* c);
string2(const string2 &c);
~string2();
string2 & operator=(const string2 &c);
//功能
int has(const char ch);//返回ch在str中出现的次数
void stringup();
void stringlow();
//重载运算符
friend string2 operator+(const string2 &b,const string2 &c);//要返回一个对象。调用复制构造函数
friendbooloperator==( const string2 &b,const string2 &c);
friendstd::ostream & operator<<(std::ostream & os,const string2 &c);
friendstd::istream & operator>>(std::istream & os, string2 &c);
};
#endif

#include <iostream>
#include <cctype>
#include <cstring>
string2::string2()
{

// *********************
len = 0;

str = new char;
str='\0';
}
string2::string2(const char* c)
{
len = strlen(c);
str = new char;
strcpy(str,c);

}
string2::string2(const string2 &c)
{
len = strlen(c.str);
str = new char;
strcpy(str,c.str);
}
string2::~string2()
{
std::cout<<"/"<<str<<"/"<<std::endl; //       ---------------------------------标记被删除的对象
delete []str;

}

int string2::has(const char ch)
{
int count = 0;
char *p = str;
while(*p != '\0')
   if(*p++ == ch)
         count++;
return count;
/*
int count = 0;
while(*str++ !='\0')
   if(*str==ch)
         count++;

return count;
*/
}
void string2::stringup()
{
for(int i=0;i<len;i++)
   if(islower(str))
         str=str-32;
}
void string2::stringlow()
{
for(int i=0;i<len;i++)
   if(isupper(str))
         str=str+32;
}
string2 & string2::operator=(const string2 &c)
{
if(this == &c)
   return *this;
delete []str;
len = strlen(c.str);
str = new char;
strcpy(str,c.str);
return *this;
}
string2 operator+(const string2 &b,const string2 &c)
{
string2 s;

// ************************
delete []s.str;

s.len = b.len +c.len;
s.str = new char;//给出充足地址；
strcpy(s.str, b.str);
strcat(s.str, c.str);
return s;
}
bool operator==(const string2 &b,const string2 &c)
{
return (std::strcmp(b.str,c.str)==0);
}
std::ostream& operator<<(std::ostream &os,const string2 &c)
{
os <<c.str<<std::endl;
return os;
}
std::istream & operator>>(std::istream & is, string2 & c)
{
char temp;
is.get(temp, 20);
if (is)
   c = temp;
while (is && is.get() != '\n')
   continue;          //删除多余的字符
return is;
}

#include <iostream>
using namespace std;
int main()
{
string2 s1(" and I am a C++ student. ");
string2 s2= "Please enter your name: ";
string2 s3;
cout << s2;
cin >>s3;
s2 = "My name is "+s3;
cout<<s2<<std::endl;
s2=s2 +s1;
s2.stringup();
cout<<"The string\n"<<s2<<"\ncontains "<<s2.has('A')<<" 'A' characters in it.\n";
s1= "red";
string2 rgb={string2(s1),string2("green"),string2("blue")};
cout<<"Enter the name of a primary color for mixing light: ";
string2 ans;
bool success = false;
while(cin>>ans)
{
   ans.stringlow();
   for(int i =0;i<3;i++)
   {
         if(ans==rgb)
         {
            cout<<"That's right!\n";
            success =true;
            break;
         }
   }
   if(success)
         break;
   else
   {
         cout<<"Try again1\n";
   }
   cout<<"Bye\n";
   return 0;
}
}

沐丶心 发表于 2021-4-14 19:20:59

明白了str的两块内存冲突了。谢谢大佬{:10_264:}

页: [1]

鱼C论坛's Archiver

使用对象时内存泄漏