C++ 如何使<&书信电报;操作员是否打印类成员?
这是上课时间C++ 如何使<&书信电报;操作员是否打印类成员?,c++,class,operator-overloading,runtime-error,graph-theory,C++,Class,Operator Overloading,Runtime Error,Graph Theory,这是上课时间 class graph { public: graph() {}; // constructor graph(int size); friend ostream& operator<< (ostream& out, graph g); private: int size; bool** grph; }; 类图{ 公众: graph(){};/
class graph {
public:
graph() {}; // constructor
graph(int size);
friend ostream& operator<< (ostream& out, graph g);
private:
int size;
bool** grph;
};
类图{
公众:
graph(){};//构造函数
图形(整数大小);
friend ostream&operator从不输入循环,因为
i < g.size
另外,您没有指定复制构造函数,因此将使用隐式构造函数。但是隐式构造函数只是复制值,因此指针grph
将指向相同数据的两个对象。您正在泄漏内存,这就是为什么(技术上)不重要的原因,但您应该实现适当的析构函数和复制/移动构造函数
但是因为操作符问题取决于类属性大小的初始化失败
在costructor方法中
添加到ctorthis.size=size
应该可以解决您的问题,正如Rakete1111正确指出的那样
以下方法允许您打印false或true,否则除了其他人所说的之外,您还可以尝试cout(您没有初始化size
成员),你的运算符如果为true,这只是问题的一部分。看运算符的签名,然后看OP为类提供的c'tor。@NathanOliver,我看不到。它们是一样的?OP正在制作副本。他们有副本c'tor吗?@Galik解决了大小问题,但没有解决打印问题,打印是专业的问题。现在他们将打印浅拷贝,这将(希望如此)导致访问冲突。@Galik oops。我看错了。回答这个问题没问题。谢谢你直截了当地回答。虽然这个代码片段可能会解决这个问题,但确实有助于提高你文章的质量。记住,你是在将来为读者回答这个问题,那些人可能会问I don’我不知道你的代码建议的原因。我更好地了解了你的构造函数,实际上原因是“size”属性的初始化失败……这个类还需要重载一些函数以适应复制。这篇文章应该很有用:
ostream& operator<< (ostream& out, graph g) {
for (int i = 0; i < g.size; ++i) {
for (int j = 0; j < g.size; ++j)
out << g.grph[i][j] << "\t";
out << endl;
}
return out;
}
graph g(5);
cout << g << endl;
i < g.size
this->size = size; //Sets member variable 'size' to 'size' from the function arguments
ostream& operator<< (ostream& out, graph g) {
for (int i = 0; i < g.size; ++i) {
for (int j = 0; j < g.size; ++j)
out << (g.grph[i][j] ? "true" : "false") << "\t";
out << endl;
}
return out;
}
ostream& operator<< (ostream& out, const graph &g)
class graph {
public:
graph(int size = 0);
graph(const graph &src);
~graph();
graph& operator=(const graph &rhs);
friend std::ostream& operator<< (std::ostream& out, const graph &g);
private:
int size;
bool** grph;
};
std::ostream& operator<< (std::ostream& out, const graph &g);
graph::graph(int size)
: grph(NULL), size(size)
{
grph = new bool*[size];
for (int i = 0; i < size; ++i) {
grph[i] = new bool[size];
}
for (int i = 0; i < size; ++i) {
for (int j = i; j < size; ++j) {
if (i == j) {
grph[i][j] = false;
} else {
grph[i][j] = grph[j][i] = (prob() < 0.19);
}
}
}
}
graph::graph(const graph &src)
: grph(NULL), size(src.size)
{
grph = new bool*[size];
for (int i = 0; i < size; ++i) {
grph[i] = new bool[size];
for (int j = i; j < size; ++j) {
grph[i][j] = src.grph[i][j];
}
}
graph::~graph() {
for (int i = 0; i < size; ++i) {
delete[] grph[i];
}
delete[] grph;
}
graph& graph::operator=(const graph &rhs)
{
if (this != &rhs)
{
graph tmp(rhs);
std::swap(grph, tmp.grph);
std::swap(size, tmp.size);
}
return *this;
}
std::ostream& operator<< (std::ostream& out, const graph &g) {
for (int i = 0; i < g.size; ++i) {
for (int j = 0; j < g.size; ++j) {
out << g.grph[i][j] << "\t";
}
out << endl;
}
return out;
}
class graph {
public:
graph(int size = 0);
friend ostream& operator<< (ostream& out, const graph &g);
private:
std::vector<std::vector<bool> > grph;
};
std::ostream& operator<< (std::ostream& out, const graph &g);
graph::graph(int size)
{
grph.resize(size);
for (int i = 0; i < size; ++i) {
grph[i].resize(size);
}
for (int i = 0; i < size; ++i) {
for (int j = i; j < size; ++j) {
if (i == j) {
grph[i][j] = false;
} else {
grph[i][j] = grph[j][i] = (prob() < 0.19);
}
}
}
}
ostream& operator<< (ostream& out, const graph &g) {
for (int i = 0; i < g.grph.size(); ++i) {
std:::vector<bool> &row = g.grph[i];
for (int j = 0; j < row.size(); ++j) {
out << row[j] << "\t";
}
out << endl;
}
return out;
}