正常块后检测到堆损坏（#181）

Question

（首先对不起英语，因为我不擅长英语）

我已经为幻方写了一个代码，它工作正常并给出了真实的平方。

当它被编译并且我运行程序时，没有任何问题。

但是当它到达 main() 中的 return 0 时，我得到这个错误

heap corruption detected after normal block (#180)

我搜索了一下，发现我的square class不符合三规则(What is The Rule of Three?)

所以我试了一下，但又遇到了错误。

这是我的代码。

#include<iostream>


using namespace std;

class square {

public:
//a n*n square which n=size
    int size;
//a set of blocks in square which is declared
//by pointers cuz i couldn't simply write block[size][size]
    int** block = new int*[size];
    square(const int _size) {
        size = _size;
        for (int c = 0;c < size;c++) {
            block[c] = new int[size];
        }
//putting 0 value in all blocks
        for (int i = 0; i < size;i++)
            for (int j = 0;j < size;j++) {
                block[i][j] = 0;
            }
    }
//distructor
    ~square() {
        for (int c = 0; c < size; c++)
            delete block[c];

        delete block;
    }
//copy constructor
    square(const square& that) {
        for (int c = 0; c < size; c++)
            delete block[c];

        delete block;
        size = that.size;
        block = new int*[size];
        for (int c = 0;c < size;c++) {
            block[c] = new int[size];
        }
        for (int i = 0; i < size;i++)
            for (int j = 0;j < size;j++) {
                block[i][j] = that.block[i][j];
            }
    }
//add or change the value of a block
    void add_block(int &value, int i, int j) {
        block[i][j] = value;
    }
//get the value stored in a block
    int get_block(int i, int j) {
        return block[i][j];
    }
//get the size of the square
    int get_size() {
        return size;
    }
//display the square
    void disp() {
        for (int i = 0; i < size;i++) {
            for (int j = 0;j < size;j++) {
                cout << block[i][j]<<' ';
            }
            cout << endl;
        }

    }


};
//just to write clean code i made this function
//to get the size of the square from input
int intro() {
    cout << "magic square" << endl;
    cout << "what's the size of rows and columns?(just enter an integer and must be one of the following numbers)" << endl;
    cout << "3 , 5 , 7 , ... , (2n+1)" << endl;
    int s_size;
    cin >> s_size;
    while (s_size % 2 == 0) {
        cout << "!!! must be one of the following numbers : 3 , 5 , 7 , ... , (2n+1) !!!" << endl;
        cout << "enter again" << endl;
        cin >> s_size;
    }
    return s_size;
}
//look for next valid block to add the next number
//and adding the next number
//the algorithm is go up.go left.if not filled before
//put new number. else go back to last position.go down.put the number.
void add_next_magic_block(square &s,int &v,int &i , int &j) {
    int s_size = s.get_size();
    int ii = i;
    int jj = j;
    if (i == 0)
        i = s_size - 1;
    else
        i--;
    if (j == s_size - 1)
        j = 0;
    else
        j++;
    if (s.get_block(i, j) == 0)
        s.add_block(v, i, j);
    else {
        s.add_block(v, ++ii, jj);
        i = ii;
        j = jj;
    }
}
//magic square which starts from [0][j/2]
//and ends when it reaches to the 
//size*size 
//which is the last number
void do_magic_square_on(square &s) {
    int end = s.get_size()*s.get_size();
    int count=1;
    int i = 0;
    int j = s.get_size() / 2;
    s.add_block(count, 0, j);
    count++;

    while (count <= end) {
        add_next_magic_block(s, count, i, j);
        count++;
    }
}


int main() {
    int s_size = intro();
    square my_s(s_size);

    do_magic_square_on(my_s);

    my_s.disp();
    system("pause");
    return 0;
}

与问答无关这是编辑后的代码这是 link 到运行的新代码 http://cpp.sh/72mmg

#include<iostream>


using namespace std;

class magic_square {

public:


    int size;
    int** block;
    magic_square(int _size) :size(_size) , block(new int*[size]) {
        size = _size;
        for (int c = 0;c < size;c++) {
            block[c] = new int[size];
        }
        for (int i = 0; i < size;i++)
            for (int j = 0;j < size;j++) {
                block[i][j] = 0;
            }
    }

    ~magic_square() {
        for (int c = 0; c < size; c++)
            delete block[c];

        delete block;
    }

    magic_square(const magic_square& that) {
        for (int c = 0; c < size; c++)
            delete block[c];

        delete block;
        size = that.size;
        block = new int*[size];
        for (int c = 0;c < size;c++) {
            block[c] = new int[size];
        }
        for (int i = 0; i < size;i++)
            for (int j = 0;j < size;j++) {
                block[i][j] = that.block[i][j];
            }
    }

    void add_block(int &value, int i, int j) {
        block[i][j] = value;
    }

    int get_block(int i, int j) {
        return block[i][j];
    }

    int get_size() {
        return size;
    }

    int sum_of_row(int row) {
        int sum = 0;
        int c = 0;
        for (int c = 0; c < this->get_size(); c++)
            sum += this->get_block(row, c);
        return sum;
    }

    int sum_of_col(int col) {
        int sum = 0;
        int c = 0;
        for (int c = 0; c < this->get_size(); c++)
            sum += this->get_block(c, col);
        return sum;
    }

    void disp() {
        for (int i = 0; i < size;i++)
            cout << '\t' << "["<<i+1<<"]";
        cout <<'\t'<<"row sum"<< endl << endl;
        for (int i = 0; i < size;i++) {
            cout << "[" << i + 1 << "]";
            for (int j = 0;j < size;j++) {
                cout<<'\t'<< block[i][j];
            }
            cout <<'\t'<<sum_of_row(i) <<endl;
        }
        cout <<endl <<"col sum";
        for (int i = 0; i < size;i++)
            cout << '\t'<< sum_of_col(i);
        cout << endl;
    }


};

int intro() {
    cout << "magic square" << endl;
    cout << "what's the size of rows and columns?(just enter an integer and must be one of the following numbers)" << endl;
    cout << "3 , 5 , 7 , ... , (2n+1)" << endl;
    int s_size;
    cin >> s_size;
    while (s_size % 2 == 0) {
        cout << "!!! must be one of the following numbers : 3 , 5 , 7 , ... , (2n+1) !!!" << endl;
        cout << "enter again" << endl;
        cin >> s_size;
    }
    return s_size;
}

void add_next_magic_block(magic_square &s,int &v,int &i , int &j) {
    int s_size = s.get_size();
    int ii = i;
    int jj = j;
    if (i == 0)
        i = s_size - 1;
    else
        i--;
    if (j == s_size - 1)
        j = 0;
    else
        j++;
    if (s.get_block(i, j) == 0)
        s.add_block(v, i, j);
    else {
        s.add_block(v, ++ii, jj);
        i = ii;
        j = jj;
    }
}

void normal_do_magic_square_on(magic_square &s) {
    int end = s.get_size()*s.get_size();
    int count = 1;
    int i = 0;
    int j = s.get_size() / 2;
    s.add_block(count, 0, j);

    //cout <<endl<< "   <------STEP------>  "<< "[" << count << "]" << endl<<endl;
    //s.disp();
    //cout << endl;

    count++;
    while (count <= end) {
        add_next_magic_block(s, count, i, j);

        //cout << endl << " <------STEP------>  " << "["<<count<<"]" << endl << endl;
        //s.disp();
        //cout << endl;

        count++;
    }
}

void step_do_magic_square_on(magic_square &s) {
    int end = s.get_size()*s.get_size();
    int count=1;
    int i = 0;
    int j = s.get_size() / 2;
    s.add_block(count, 0, j);

    cout <<endl<< " <------STEP------>  "<< "[" << count << "]" << endl<<endl;
    s.disp();
    cout << endl;

    count++;
    while (count <= end) {
        add_next_magic_block(s, count, i, j);

        cout << endl << "   <------STEP------>  " << "["<<count<<"]" << endl << endl;
        s.disp();
        cout << endl;

        count++;
    }
}

//to decide if show the steps or no
void out_put(magic_square &s) {
    cout << "want to see the steps?(y,n)";
    char in;
    cin >> in;
    if (in == 'n' || in == 'N') {
        normal_do_magic_square_on(s);
        s.disp();
    }

    else if(in=='y' || in=='Y')
        step_do_magic_square_on(s);
}

int main() {
    int s_size = intro();
    magic_square my_s(s_size);
    out_put(my_s);
    system("pause");
    return 0;
}

Answer 1

实际上，当您尝试为块分配内存时会发生错误，此处

int** block = new int*[size];

那是因为您的成员变量 size 在您的代码的此时没有初始化并且包含垃圾。我的建议是在构造函数中初始化两个变量，像这样：

int size;
int** block
square(int _size) : size(_size), block(new int*[size]) {
    size = _size;
    for (int c = 0; c < size; c++) {
        block[c] = new int[size];
    }
    for (int i = 0; i < size; i++)
        for (int j = 0; j < size; j++) {
            block[i][j] = 0;
        }
}

请注意，因为在上面的代码中我决定初始化size，然后用它来初始化block，size 必须定义 before block。如果您将声明的顺序更改为

int** block
int size;

代码将再次使用未初始化的 size。

正常块后检测到堆损坏（#181）

heap corruption detected after normal block (#181)

c++

heap-memory

rule-of-three

heap-corruption