该代码将编译并运行，并创建预期的输出，除非运行valgrind时才会出现这些内存泄漏。以下代码在Visual Studio上运行，不会出现任何警告或错误。
所以我的问题是，此内存泄漏发生在哪里？我是CPP的新手，已经花了数小时的时间，所以这些错误让我感到惊讶。
就顺序而言，我有做错什么吗？我在某个地方传递未初始化的值吗？困惑。
我在弄清楚发生内存丢失的位置时遇到了麻烦。这些是文件:
/// Saiyan.cpp
#define _CRT_SECURE_NO_WARNINGS
#include <string.h>
#include <iostream>
#include "Saiyan.h"
using namespace std;
namespace sdds
{
// CONSTRUCTORS:
Saiyan::Saiyan()
{
// default state
m_name = nullptr; // Dynamic allocation: set to nullptr!
m_dob = 0;
m_power = 0;
m_super = false;
m_level = 0;
}
Saiyan::Saiyan(const char* name, int dob, int power)
{
set(name, dob, power);
}
// MEMBER FUNCTIONS:
void Saiyan::set(const char* name, int dob, int power, int level, bool super)
{
// Check if arguments are valid:
if (name == nullptr || strlen(name) <= 0 || dob > 2020 || power <= 0)
{
*this = Saiyan(); // Calls constructor that creates default.
}
else
{
// Deallocate previosly allocated memory for m_name to avoid memory leak:
if (m_name != nullptr && strlen(name) == 0)
{
delete[] m_name;
m_name = nullptr;
}
// Assign validate values to current object:
m_name = new char[strlen(name) + 1];
strcpy(m_name, name);
m_dob = dob;
m_power = power;
m_super = super;
m_level = level;
}
}
bool Saiyan::isValid() const
{
bool valid_state = m_name != nullptr && strlen(m_name) > 0 && m_dob < 2020 && m_power > 0;
return valid_state;
}
void Saiyan::display() const
{
if (isValid())
{
cout << m_name << endl;
cout.setf(ios::right);
cout.width(10);
cout << "DOB: " << m_dob << endl;
cout.width(10);
cout << "Power: " << m_power << endl;
cout.width(10);
if (m_super == true) {
cout << "Super: " << "yes" << endl;
cout.width(10);
cout << "Level: " << m_level;
}
else
{
cout << "Super: " << "no";
}
cout.unsetf(ios::left);
}
else
{
cout << "Invalid Saiyan!";
}
cout << endl;
}
bool Saiyan::fight(Saiyan& other)
{
// Check both Saiyans for super level and power up accordingly:
if (m_super == true)
{
m_power += int(m_power * (.1 * m_level)); // Cast an int to avoid possible memory loss.
}
if (other.m_super == true)
{
other.m_power += int(other.m_power * (.1 * other.m_level));
}
bool value = m_power > other.m_power;
return value;
}
// DESTRUCTOR:
Saiyan::~Saiyan()
{
if (m_name != nullptr)
{
delete[] m_name; // Deallocate memory of member.
m_name = nullptr;
}
}
}
// Saiyan.h
#pragma once
#ifndef SDDS_SAIYAN_H
#define SDDS_SAIYAN_H
namespace sdds
{
class Saiyan
{
char* m_name; // Dynamically allocated array of chars.
int m_dob; // Year the Saiyan was born.
int m_power; // Integer indicating the strength of the Saiyan (>= 0).
bool m_super; // indicates whether Saiyan can evolve
int m_level; // an integer indicating the level of a SS
/*
***Valid Name*** : a dynamically allocated array of chars.
***Valid Year of Birth***: an integer within the interval[0, 2020].
***Valid Power***: an integer that is greater than 0.
*/
public:
Saiyan();
Saiyan(const char* name, int dob, int power); // Custom constructor
void set(const char* name, int dob, int power, int level = 0, bool super = false);
bool isValid() const;
void display() const;
bool fight(Saiyan& other); // Fight and power up Saiyans.
~Saiyan();
};
}
#endif
// main.cpp
#include <iostream>
#include "Saiyan.h"
#include "Saiyan.h" // this is on purpose
using namespace std;
using namespace sdds;
void printHeader(const char* title)
{
char oldFill = cout.fill('-');
cout.width(40);
cout << "" << endl;
cout << "|> " << title << endl;
cout.fill('-');
cout.width(40);
cout << "" << endl;
cout.fill(oldFill);
}
int main()
{
{
printHeader("T1: Checking default constructor");
Saiyan theSayan;
theSayan.display();
cout << endl;
}
{
printHeader("T2: Checking custom constructor");
Saiyan army[] = {
Saiyan("Nappa", 2025, 1),
Saiyan("Vegeta", 2018, -1),
Saiyan("Goku", 1990, 200),
Saiyan(nullptr, 2015, 1),
Saiyan("", 2018, 5)
};
cout << "Only #2 should be valid:" << endl;
for (int i = 0; i < 5; i++)
{
cout << " Sayan #" << i << ": " << (army[i].isValid() ? "valid" : "invalid") << endl;
}
for (int i = 0; i < 5; i++)
{
army[i].display();
}
cout << endl;
}
// valid saiyans
Saiyan s1("Goku", 1990, 2000);
Saiyan s2;
s2.set("Vegeta", 1989, 2200);
{
printHeader("T3: Checking the fight");
s1.display();
s2.display();
cout << "S1 attacking S2, Battle " << (s1.fight(s2) ? "Won" : "Lost") << endl;
cout << "S2 attacking S1, Battle " << (s2.fight(s1) ? "Won" : "Lost") << endl;
cout << endl;
}
{
printHeader("T4: Checking powerup");
s1.set("Goku", 1990, 1900, 1, true);
int round = 0;
bool gokuWins = false;
while (!gokuWins) // with every fight, the super saiyan should power up
{
cout << "Round #" << ++round << endl;
gokuWins = s1.fight(s2);
s1.display();
s2.display();
}
cout << "Bonus round. Is s2 winning? " << (s2.fight(s1) ? "yes" : "no") << endl;
s1.display();
s2.display();
cout << endl;
}
{
printHeader("T5: Upgrading s2");
s2.set("Vegeta", 1990, 2200, 3, true);
cout << "Super Battle. Is s2 winning? " << (s2.fight(s1) ? "yes" : "no") << endl;
s1.display();
s2.display();
cout << endl;
}
return 0;
}
/// Saiyan.cpp
#define _CRT_SECURE_NO_WARNINGS
#include <string.h>
#include <iostream>
#include "Saiyan.h"
using namespace std;
namespace sdds
{
Saiyan::Saiyan()
{
}
Saiyan::Saiyan(const char* name, int dob, int power)
{
set(name, dob, power);
}
void Saiyan::set(const char* name, int dob, int power, int level, bool super)
{
if (name != nullptr && name[0] != '\0')
{
if (m_name != nullptr)
{
delete[] m_name;
m_name = nullptr;
}
m_name = new char[strlen(name) + 1];
strcpy(m_name, name);
}
if (dob != 0 && dob < 2020)
{
m_dob = dob;
}
if (power > 0)
{
m_power = power;
}
if (level > 0)
{
m_level = level;
}
m_super = super;
}
bool Saiyan::isValid() const
{
bool valid_state = m_name != nullptr && m_dob != 0 && m_dob < 2020 && m_power > 0 && m_level >= 0;
return valid_state;
}
void Saiyan::display() const
{
if (isValid())
{
cout << m_name << endl;
cout.setf(ios::right);
cout.width(10);
cout << "DOB: " << m_dob << endl;
cout.width(10);
cout << "Power: " << m_power << endl;
cout.width(10);
if (m_super == true) {
cout << "Super: " << "yes" << endl;
cout.width(10);
cout << "Level: " << m_level;
}
else
{
cout << "Super: " << "no";
}
cout.unsetf(ios::left);
}
else
{
cout << "Invalid Saiyan!";
}
cout << endl;
}
bool Saiyan::fight(Saiyan& other)
{
// Check both Saiyans for super level and power up accordingly:
if (m_super == true)
{
m_power += int(m_power * (.1 * m_level)); // Cast an int to avoid possible memory loss.
}
if (other.m_super == true)
{
other.m_power += int(other.m_power * (.1 * other.m_level));
}
bool value = m_power > other.m_power;
return value;
}
Saiyan::~Saiyan()
{
if (m_name != nullptr)
{
delete[] m_name; // Deallocate memory of member.
m_name = nullptr;
}
}
}
// Saiyan.h
#pragma once
#ifndef SDDS_SAIYAN_H
#define SDDS_SAIYAN_H
namespace sdds
{
class Saiyan
{
char* m_name{}; // Dynamically allocated array of chars.
int m_dob{}; // Year the Saiyan was born.
int m_power{}; // Integer indicating the strength of the Saiyan (>= 0).
bool m_super{}; // indicates whether Saiyan can evolve
int m_level{}; // an integer indicating the level of a SS
/*
***Valid Name*** : a dynamically allocated array of chars.
***Valid Year of Birth***: an integer within the interval[0, 2020].
***Valid Power***: an integer that is greater than 0.
*/
public:
Saiyan();
Saiyan(const char* name, int dob, int power); // Custom constructor
void set(const char* name, int dob, int power, int level = 0, bool super = false);
bool isValid() const;
void display() const;
bool fight(Saiyan& other); // Fight and power up Saiyans.
~Saiyan();
};
}
#endif
最佳答案
通常---避免手动内存管理，为什么不只使用std::string？
关于代码中的问题。
这部分代码很重要:
if (name == nullptr || strlen(name) <= 0 || dob > 2020 || power <= 0)
{
*this = Saiyan(); // Calls constructor that creates default.
}
另一个问题是在此构造函数中:
Saiyan::Saiyan(const char* name, int dob, int power)
{
set(name, dob, power);
}
最后但并非最不重要的是，在这里:
if (m_name != nullptr && strlen(name) == 0)
{
delete[] m_name;
m_name = nullptr;
}
同样在C++ 11中，您可以为构造函数外部的成员提供默认值，并且它们将在每个您没有显式设置其他值的构造函数中使用:
class Saiyan
{
char* m_name = nullptr; // Dynamically allocated array of chars.
int m_dob = 0; // Year the Saiyan was born.
int m_power = 0; // Integer indicating the strength of the Saiyan (>= 0).
bool m_super = false; // indicates whether Saiyan can evolve
int m_level = 0; // an integer indicating the level of a SS
public:
Saiyan() {};
...
关于c++ - CPP中的Valgrind和内存泄漏: “Conditional jump or move depends on uninitialised values”，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/62498819/