执行时指针矩阵错误

Question

        class Matrix{
            double **val;
            int rows,cols,errorCode;
        public:
            Matrix();
            Matrix(int);
            Matrix(int, int);
            ~Matrix();
            void Print();
            void Read();
            double Get(int, int);
            void Assign(int,int,double);
            void Addition(Matrix&);
            void Subtraction(Matrix&);
            Matrix Multiply(Matrix&);
            void Multiply(double);
        };

    Matrix::Matrix(){
        //First array go with rows.
        val = new double*[1];
        val[1] = new double[1];
        rows = 1;
        cols = 1;
        errorCode = 0;
    }

    Matrix::Matrix(int n){
        rows = n;
        cols = n;
        val = new double*[rows];
        for(int i = 0;i<rows;i++){
            val[i] = new double[cols];
        }
    }

    Matrix::Matrix(int n,int m){
        rows = n;
        cols = m;
        val = new double*[rows];
        for(int i = 0;i<rows;i++){
            val[i] = new double[cols];
        }
    }

    Matrix::~Matrix(){
        for(int i=0;i<rows;i++){
            delete[] val[i];
        }
        delete[] val;
    }

Matrix Matrix::Multiply(Matrix &a){
            if(cols != a.rows){
                Matrix b;
                b.errorCode=111; //That means dimensions are not valid;
                return b;
            }
            else{
                Matrix b(rows,a.cols);
                double  p;
                for(int i=0;i<rows;i++){
                    for(int j=0;j<a.cols;j++){
                        p=0;
                        for(int k=0;k<cols;k++){p += val[i][k]*a.val[k][j];}
                        b.Assign(i,j,p);
                    }
                }
                return b;
            }
        }

当我编译它似乎没问题，但当我运行它不起作用，我不明白为什么...它说“程序停止工作”并返回错误255

如果需要，我可以把我写的所有代码......

我添加了构造函数......

不幸的是我无法发布图片...它说进程返回255，这是一个来自Windows的警报，程序没有正常工作并且停止工作......

以下是所有代码，如果有人有时间，如果它有助于你更好地理解..

#include <iostream>
using namespace std;

class Matrix{
    double **val;
    int rows,cols,errorCode;
public:
    Matrix();
    Matrix(int);
    Matrix(int, int);
    ~Matrix();
    void Print();
    void Read();
    double Get(int, int);
    void Assign(int,int,double);
    void Addition(Matrix&);
    void Subtraction(Matrix&);
    Matrix Multiply(Matrix&);
    void Multiply(double);
};

Matrix::Matrix(){
    //First array go with rows.
    val = new double*[1];
    val[0] = new double[1];
    rows = 1;
    cols = 1;
    errorCode = 0;
}

Matrix::Matrix(int n){
    rows = n;
    cols = n;
    val = new double*[rows];
    for(int i = 0;i<rows;i++){
        val[i] = new double[cols];
    }
}

Matrix::Matrix(int n,int m){
    rows = n;
    cols = m;
    val = new double*[rows];
    for(int i = 0;i<rows;i++){
        val[i] = new double[cols];
    }
}

Matrix::~Matrix(){
    for(int i=0;i<rows;i++){
        delete[] val[i];
    }
    delete[] val;
}

void Matrix::Read(){

    for(int i=0;i<rows;i++){
        delete[] val[i];
    }
    delete[] val;
    cout<<"Give the matrix dimensions (rows and cols) : ";
    cin>>rows>>cols;
    val = new double*[rows];
    for(int i = 0;i<rows;i++){
        val[i] = new double[cols];
    }
    cout<<"Give the matrix values: "<<endl;
    for(int i = 0;i<rows;i++){
        for(int j = 0;j<cols;j++){ cin>>val[i][j];}
    }

}

void Matrix::Print(){
    cout<<"The matrix with "<<rows<<" rows and "<<cols<<" cols, have next values: "<<endl;
    for(int i = 0;i<rows;i++){
        for(int j = 0;j<cols;j++){ cout<<val[i][j]<<" ";}
        cout<<endl;
    }
}

double Matrix::Get(int n, int m){
    return val[n-1][m-1];
}

void Matrix::Assign(int n,int m,double v){
    val[n-1][m-1] = v;
}

void Matrix::Addition(Matrix &a){
    if(rows != a.rows || cols !=a.cols){
        errorCode=111; //That means dimensions are not equal;
    }
    else{
        for(int i = 0;i<rows;i++){
            for(int j = 0;j<cols;j++){ val[i][j] += a.val[i][j];}
        }
    }
}


void Matrix::Subtraction(Matrix &a){
    if(rows != a.rows || cols !=a.cols){
        errorCode=111; //That means dimensions are not equal;
    }
    else{
        for(int i = 0;i<rows;i++){
            for(int j = 0;j<cols;j++){ val[i][j] -=a.val[i][j];}
        }
    }
}

void Matrix::Multiply(double x){
     for(int i = 0;i<rows;i++){
            for(int j = 0;j<cols;j++){ val[i][j] *= x;}
        }
}

Matrix Matrix::Multiply(Matrix &a){
    if(cols != a.rows){
        errorCode=111; //That means dimensions are not equal;
        Matrix b;
        return b;
    }
    else{
        Matrix b(rows,a.cols);
        double  p;
        for(int i=0;i<rows;i++){
            for(int j=0;j<a.cols;j++){
                p=0;
                for(int k=0;k<cols;k++){p += val[i][k]*a.val[k][j];}
                b.Assign(i,j,p);
            }
        }
        return b;
    }
}

int main(){

Matrix a,b(2,3);
b.Assign(1,1,0);
b.Assign(1,2,3);
b.Assign(1,3,5);
b.Assign(2,1,5);
b.Assign(2,2,5);
b.Assign(2,3,2);
b.Print();

a.Read();
a.Print();
cout<<endl;
//when i read a i put 3x2 matrix, so the multiplying can be done.
Matrix c=a.Multiply(b);
c.Print();
return 0;

}

当我尝试使用函数时出现

问题：Matrix Multiply（Matrix＆amp;）。

Answer 1

默认构造函数中存在错误：

    val = new double*[1];
    val[1] = new double[1];

1不是val的有效索引，应该是：

    val[0] = new double[1];