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问题： 这个简单的矩阵类C++为什么会报错？
描述: #include
using namespace std;
class matrix
{
public:
matrix(int,int);
void set_m();
matrix operator~();
void display();
matrix(matrix&);
~matrix(){ delete m; };
private:
int lin,col;
int **m;
}
matrix::matrix(int a,int b)
{
lin=a;
col=b;
m=new int*[lin];
for(int i=0;i<>
m[i]=new int[col];
}
matrix::matrix(matrix& mp)
{
lin=mp.lin;
col=mp.col;
m=new int*[lin];
for(int i=0;i<>
m[i]=new int[col];
}
void matrix::set_m()
{
cout<<"please input the matrix:\n";
for(int i=0;i<>
for(int j=0;j<>
cin>>m[i][j];
}
matrix matrix::operator~()
{
matrix C(col,lin);
for(int i=0;i<>
for(int j=0;j<>
C.m[j][i]=m[i][j];
return C;
}
void matrix::display()
{
for(int i=0;i<>
{
for(int j=0;j<>
cout<<>
cout<<>
}
}
int main()
{
int al,ac;
cout<<"please input the first matrix's lin and col:\n";
cin>>al>>ac;
matrix A(al,ac);
A.set_m();
(~A).display();
cout<<>
return 0;
}
自己编的一个矩阵类，求转置的，编译报错说“constructors not allowed a return type”，但这个构造函数似乎没有返回类型啊，难道是动态分配内存的问题？
解决方案1: 在类定义或者申明时,结束的地方忘了加个'; '
解决方案2:
// Miscellaneous -methods
void Null (const size_t& row, const size_t& col) _NO_THROW;
void Null () _NO_THROW;
void Unit (const size_t& row) _NO_THROW;
void Unit () _NO_THROW;
void SetSize (size_t row, size_t col) _NO_THROW;
// Utility methods
matrixT Solve (const matrixT& v) const _THROW_MATRIX_ERROR;
matrixT Adj () _THROW_MATRIX_ERROR;
matrixT Inv () _THROW_MATRIX_ERROR;
T Det () const _THROW_MATRIX_ERROR;
T Norm () _NO_THROW;
T Cofact (size_t row, size_t col) _THROW_MATRIX_ERROR;
T Cond () _NO_THROW;
// Type of matrices
bool IsSquare () _NO_THROW { return (_m->Row == _m->Col); }
bool IsSingular () _NO_THROW;
bool IsDiagonal () _NO_THROW;
bool IsScalar () _NO_THROW;
bool IsUnit () _NO_THROW;
bool IsNull () _NO_THROW;
bool IsSymmetric () _NO_THROW;
bool IsSkewSymmetric () _NO_THROW;
bool IsUpperTriangular () _NO_THROW;
bool IsLowerTriangular () _NO_THROW;
private:
struct base_mat
{
T **Val;
size_t Row, Col, RowSiz, ColSiz;
int Refcnt;
base_mat (size_t row, size_t col, T** v)
{
Row = row; RowSiz = row;
Col = col; ColSiz = col;
Refcnt = 1;
Val = new T* [row];
size_t rowlen = col * sizeof(T);
for (size_t i=0; i < row; i++)
{
Val[i] = new T [col];
if (v) memcpy( Val[i], v[i], rowlen);
}
}
~base_mat ()
{
for (size_t i=0; i < RowSiz; i++)
delete [] Val[i];
delete [] Val;
}
};
base_mat *_m;
void clone ();
void realloc (size_t row, size_t col);
int pivot (size_t row);
};
#if defined(_MSC_VER) && _MSC_VER <= 1020
# undef _NO_THROW // MSVC++ 4.0/4.2 does not support
# undef _THROW_MATRIX_ERROR // exception specification in definition
# define _NO_THROW
# define _THROW_MATRIX_ERROR
#endif
// constructor
MAT_TEMPLATE inline
matrixT::matrix (size_t row, size_t col)
{
_m = new base_mat( row, col, 0);
}
// copy constructor
MAT_TEMPLATE inline
matrixT::matrix (const matrixT& m)
{
_m = m._m;
_m->Refcnt++;
}
// Internal copy constructor
MAT_TEMPLATE inline void
matrixT::clone ()
{
_m->Refcnt--;
_m = new base_mat( _m->Row, _m->Col, _m->Val);
}
// destructor
MAT_TEMPLATE inline
matrixT::~matrix ()
{
if (--_m->Refcnt == 0) delete _m;
}
// assignment operator
MAT_TEMPLATE inline matrixT&
matrixT::operator = (const matrixT& m) _NO_THROW
{
m._m->Refcnt++;
if (--_m->Refcnt == 0) delete _m;
_m = m._m;
return *this;
}
// reallocation method
MAT_TEMPLATE inline void
matrixT::realloc (size_t row, size_t col)
{
if (row == _m->RowSiz && col == _m->ColSiz)
{
_m->Row = _m->RowSiz;
_m->Col = _m->ColSiz;
return;
}
base_mat *m1 = new base_mat( row, col, NULL);
size_t colSize = min(_m->Col,col) * sizeof(T);
size_t minRow = min(_m->Row,row);
for (size_t i=0; i < minRow; i++)
memcpy( m1->Val[i], _m->Val[i], colSize);
if (--_m->Refcnt == 0)
delete _m;
_m = m1;
return;
}
// public method for resizing matrix
MAT_TEMPLATE inline void
matrixT::SetSize (size_t row, size_t col) _NO_THROW
{
size_t i,j;
size_t oldRow = _m->Row;
size_t oldCol = _m->Col;
if (row != _m->RowSiz || col != _m->ColSiz)
realloc( row, col);
for (i=oldRow; i < row; i++)
for (j=0; j < col; j++)
_m->Val[i][j] = T(0);
for (i=0; i < row; i++)
for (j=oldCol; j < col; j++)
_m->Val[i][j] = T(0);
return;
}
// subscript operator to get/set individual elements
MAT_TEMPLATE inline T&
matrixT::operator () (size_t row, size_t col) _THROW_MATRIX_ERROR
{
if (row >= _m->Row || col >= _m->Col)
REPORT_ERROR( "matrixT::operator(): Index out of range!");
if (_m->Refcnt > 1) clone();
return _m->Val[row][col];
}
// subscript operator to get/set individual elements
MAT_TEMPLATE inline T
matrixT::operator () (size_t row, size_t col) const _THROW_MATRIX_ERROR
{
if (row >= _m->Row || col >= _m->Col)
REPORT_ERROR( "matrixT::operator(): Index out of range!");
return _m->Val[row][col];
}
// input stream function
MAT_TEMPLATE inline istream&
operator >> (istream& istrm, matrixT& m)
{
for (size_t i=0; i < m.RowNo(); i++)
for (size_t j=0; j < m.ColNo(); j++)
{
T x;
istrm >> x;
m(i,j) = x;
}
return istrm;
}
// output stream function
MAT_TEMPLATE inline ostream&
operator << (ostream& ostrm, const matrixT& m)
{
for (size_t i=0; i < m.RowNo(); i++)
{
for (size_t j=0; j < m.ColNo(); j++)
{
T x = m(i,j);
ostrm << x << '\t';
}
ostrm << endl;
}
return ostrm;
}
// logical equal-to operator
MAT_TEMPLATE inline bool
operator == (const matrixT& m1, const matrixT& m2) _NO_THROW
{
if (m1.RowNo() != m2.RowNo() || m1.ColNo() != m2.ColNo())
return false;
for (size_t i=0; i < m1.RowNo(); i++)
for (size_t j=0; j < m1.ColNo(); j++)
if (m1(i,j) != m2(i,j))
return false;
return true;
}
以上介绍了“ 这个简单的矩阵类C++为什么会报错？”的问题解答，希望对有需要的网友有所帮助。
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