帮我看看这个程序哪个地方出错了！
老师说，对象矩阵没有初始化,可是我还是没有明白！谢谢阿

# include <iostream>
# include <cmath>

using namespace std;

class matrix
{
public :
    matrix (int dims);
    ~matrix();
    setmatrix(double *a);
    printM();
private:
    int index;
    double *matrixA;
};

matrix ::matrix(int dims)
{
    int index =dims;
    matrixA = new double[index * index];
}

matrix ::~matrix()
{
    delete [] matrixA;
}

matrix ::setmatrix (double *a )
{
    for (int i=0; i< index * index ; i++)
            *(matrixA + i) =  a [ i ];
}

matrix ::printM()
{
    cout << " the  matrix is "  << endl ;
    for (int i=0;i<index ;i++)
        for (int j=0;j < index ;j++)
            cout << * (matrixA + i* index +j)  << " " ;
            cout << endl ;
}


void main ()
{ 
    matrix matrix1(2);
    double a[]= {1.0, 2.0, 3.0, 4.0 } ;
    matrix1.setmatrix(a);
    matrix1.printM ( );
}


[ 此帖被seast在2007-11-30 16:48重新编辑 ]

//修改后没问题了
# include <iostream>
# include <cmath>

using namespace std;

class matrix
{
public :
    matrix (int dims);
    ~matrix();
    void setmatrix(double *a);          //这里修改，加上void
    void printM();                            //这里修改，加上void
private:
    int index;
    double *matrixA;
};

matrix ::matrix(int dims)
{
    index = dims;                  //这里修改，多了 int
    matrixA = new double[index * index];
}

matrix ::~matrix()
{
    delete [] matrixA;
}

void matrix ::setmatrix (double *a)
{
    for (int i=0; i< index * index ; i++){
            *(matrixA+i) = *(a+i);        //这也改了一下，原来的也没问题
    }           
}

void matrix ::printM()
{
    cout << " the  matrix is "  << endl ;
    for (int i=0;i<index ;i++){
        for (int j=0;j < index ;j++){
            cout << * (matrixA + i* index +j)  << " " ;
        }
        cout << endl ;
    }        //加了一对｛｝
}


int main ()          //这里修改过
{
    matrix matrix1(2);
    double a[]= {1.0, 2.0, 3.0, 4.0 } ;
    matrix1.setmatrix(a);
    matrix1.printM();        //这里修改过，少了（）
    return 0;                    //加了一条语句
}


[ 此帖被yunyue在2007-11-30 16:56重新编辑 ]

int index = dims;
这样的话，index就是局部变量