I'm trying to write a template class function for doing some basic operations with matrices. I have been struggling (a lot, for almost a week ) with memory issues, since it seems like every time i call my constructor class it corrupts the object. I am also suspecting that something is wrong when I define the overload function for the + operator, the most strange thing is that my code works fine with 2x2 matrices but nothing more than that!
I would appreciate if someone has any idea of which could be the problem! Thank you.
Here is the code:
#include<iostream>
#include<stdlib.h>
#include <stdexcept>
#include<cstring>
using namespace std;
template<class TypeData>
class Matrix{
private:
int Nrows , Ncols;
TypeData *Array_Matrix;
public:
/*Constructors---------*/
Matrix(){
Nrows = 0;
Ncols = 0;
Array_Matrix = nullptr;
}
/*Constructor with 2 parameters:*/
Matrix(int _Nrows , int _Ncols){
this -> Nrows = _Nrows;
this -> Ncols = _Ncols;
Array_Matrix = new TypeData [Nrows * Ncols];
for(int i = 0 ; i<Nrows * Ncols ; i++){Array_Matrix[i] = 0.0;}
}
/*Copy constructor:*/
Matrix ( const Matrix &_M){
this -> Nrows = _M.Nrows ;
this -> Ncols = _M.Ncols;
Array_Matrix = new TypeData [Nrows * Ncols];
for(int i = 0 ; i<Nrows * Ncols ; i++){*(Array_Matrix + i) = *(_M.Array_Matrix + i);}
}
void Set_Value(int row , int col , TypeData value){
*(Array_Matrix + Ncols*row + col) = value;}
/*---------------------------------------------------------------------------------------------------------------------*/
TypeData Get_Pos_Value(int row , int col){
if(row >= Nrows || col >= Ncols){throw std::invalid_argument( "Error!, index out of bounds!" );}
else{return *(Array_Matrix + Ncols*row + col) ;}}
TypeData *Get_Array(){ /*Method for returning a pointer to the "matrix"*/
return Array_Matrix;};
int Get_Nrows(){
return Nrows;}
int Get_Ncols(){
return Ncols;}
void Print_Matrix(){
for (int i = 0 ; i<Nrows ; i++){
cout<<endl;
for (int j = 0 ; j<Ncols ; j++){
cout<<*(Array_Matrix + Ncols*i + j)<<" ";}}cout<<endl;}
/*Operator overloading --------------------------------------------------------------------------------------------*/
Matrix operator = (const Matrix &Matrix_object){
delete [] Array_Matrix;
this -> Nrows = Matrix_object.Nrows;
this -> Ncols = Matrix_object.Ncols;
Array_Matrix = new TypeData [Nrows * Ncols];
for (int i = 0 ; i<Nrows*Ncols ; i++){Array_Matrix [i] = Matrix_object.Array_Matrix[i];}
return *this;
}
Matrix operator + (const Matrix &Matrix_object)const{
if(Matrix_object.Nrows != Nrows || Matrix_object.Ncols != Ncols)
{throw std::invalid_argument("Different siex matrices cant be added!" );}
Matrix <TypeData> Temp(0,0); Temp.Nrows = Nrows ; Temp.Ncols = Ncols;
for(int i = 0 ; i<Nrows*Ncols; i++){
//Temp.Array_Matrix[i] = Array_Matrix[i] + Matrix_object.Array_Matrix[i];
*(Temp.Array_Matrix +i) = *(Array_Matrix +i) + *(Matrix_object.Array_Matrix + i);}
return Temp;}
Matrix operator - (const Matrix &Matrix_object)const{
if(Matrix_object.Nrows != Nrows || Matrix_object.Ncols != Ncols)
{throw std::invalid_argument("Different size matrices can be substracted!" );}
Matrix <TypeData> Temp(0,0); Temp.Nrows = Nrows ; Temp.Ncols = Ncols;
for(int i = 0 ; i<Nrows*Ncols; i++){
//Temp.Array_Matrix[i] = Array_Matrix[i] - Matrix_object.Array_Matrix[i];
*(Temp.Array_Matrix +i) = *(Array_Matrix +i) - *(Matrix_object.Array_Matrix + i);}
return Temp;}
Matrix operator += (const TypeData num){
Matrix <TypeData> Temp(0,0); Temp.Nrows = Nrows ; Temp.Ncols = Ncols;
for(int i = 0 ; i<Nrows*Ncols; i++){
Temp.Array_Matrix[i] = Array_Matrix[i] + num ;} return Temp;}
Matrix operator -= (const TypeData num){
Matrix <TypeData> Temp(0,0); Temp.Nrows = Nrows ; Temp.Ncols = Ncols;
for(int i = 0 ; i<Nrows*Ncols; i++){
Temp.Array_Matrix[i] = Array_Matrix[i]- num ;} return Temp;}
~Matrix(){ delete[] Array_Matrix;}
};
Main
int main(){
int r1 , c1; cout<<"Matrix1: Enter Number of rows and columns "; cin>>r1>>c1;
Matrix <float> My_Matrix(r1 , c1);
for (int i = 0 ; i<My_Matrix.Get_Nrows() ; i++){
for (int j = 0 ; j<My_Matrix.Get_Ncols(); j++){
float value; cout<<"Type the value at: ["<<i<<"]["<<j<<"] position "; cin>>value;
My_Matrix.Set_Value(i , j , value);}}
int r2 , c2; cout<<"Matrix2: Enter Number of rows and columns "<<endl; cin>>r2>>c2;
Matrix <float> My_Matrix2(r2,c2);
for (int i = 0 ; i<My_Matrix2.Get_Nrows() ; i++){
for (int j = 0 ; j<My_Matrix2.Get_Ncols(); j++){
float value; cout<<"Type the value at: ["<<i<<"]["<<j<<"] position "; cin>>value;
My_Matrix2.Set_Value(i , j , value);}}
auto My_Matrix3 = My_Matrix + My_Matrix2;
cout<<"Add: "<<endl;
My_Matrix3.Print_Matrix();
cout<<endl;
cout<<"Testing substraction: "<<endl;
auto My_Matrix4 = My_Matrix - My_Matrix2;
cout<<"Substraction is: "<<endl;
My_Matrix4.Print_Matrix();
cout<<endl;
cout<<"Testing = operator: "<<endl;
My_Matrix4 = My_Matrix3;
cout<<"Substraction matriz is now: "<<endl;
My_Matrix4.Print_Matrix();
cout<<endl<<"as the Add matrix! "<<endl;
cout<<"Testing +=:"<<endl;
int num ; cout<<"Please enter an integer number: ";cin>>num;
(My_Matrix4 += num).Print_Matrix();
return 0;}
Matrix <TypeData> Temp(0,0);
Good news: you created a Matrix
with 0 rows, 0 columns, and 0 values total.
Temp.Nrows = Nrows ; Temp.Ncols = Ncols;
Bad news: the number of rows and columns gets clobbered to something else, then:
for(int i = 0 ; i<Nrows*Ncols; i++){
//Temp.Array_Matrix[i] = Array_Matrix[i] + Matrix_object.Array_Matrix[i];
*(Temp.Array_Matrix +i) = *(Array_Matrix +i) + *(Matrix_object.Array_Matrix + i);}
return Temp;}
... the code procedes on the assumption that the Temp.Array_Matrix
will have Nrows*Ncols
values. Of course, it doesn't. Hence the memory corruption.
The same bug occurs multiple times in the shown code.