请哪位大侠帮我编一个C语言函数

//用类来解决:
class matrix//一个矩阵类;
{
private:
int m;
int n;
double arr[8][8];
public:
matrix();
matrix(double);
void set();
void show();
friend int homotype(matrix,matrix);//是否同型;
friend int multipliable(matrix,matrix);
friend matrix operator +(matrix,matrix);
friend matrix operator -(matrix,matrix);
friend matrix add(matrix,matrix);
friend matrix minus(matrix,matrix);
friend matrix multiply(matrix,matrix);
friend matrix operator *(matrix,matrix);
friend double det(matrix);//求行列式的
//值;
int issquare()//判断是否为方阵;
{
return m==n;
}
matrix left(int,int);//求余子阵;
};

matrix matrix::left(int x,int y)
{
matrix leftmatrix;
if((x>=m)||(y>=n))
{
cout<<"errer"<<endl;
return leftmatrix;
}
/* if(!issquare())
{
cout<<"不是方阵!"<<end