To answer to a comment, the code is not already implemented. The code does not solve 3x3 systems. It lacks the "ability" to do row reduced echelon calculations or Gauss Jordan elimination (it's the same thing, here's a link that explains it http://pages.pacificcoast.net/~cazelais/251/gauss-jordan.pdf)

The code that I posted simply provides the basis. You have to write a class that inherits from my class, so it gets the Matrix information that the user puts in, afterward the new class that you write will implement the Gaus Jordan calculation. I hope this clears up the confusion

[C++]I need to write a class that solves 3x3 systems of equations (3 equations with 3 unknowns). (This is about Matrices reduced to row echelon form).

If you do don't know how to do this, please, don't answer this question! If anything is unclear just comment, and I will try to clear up the confusion.

Additionally, the class should be derived from and has a base of the class of HW.1 (So the class that is going to be written inherits from the class that I wrote in my first home work)

This is important so that it has access to the Matrix information. Here's the link to my code:

Essentially, it just needs to get expanded with another class that inherits from the first one to do the row echelon calculation.

https://repl.it/KhHC/12

#include using namespace std;

class Matrix{ private : double A[3][3]; double B[3][3]; double result[3][3]; public : /*------------------------------------------------------- FUNCTON NAME: input PARAMETERS: RETURN TYPE: DESCRIPTION: Stores user values inside the corresponding arrays to be referenced later -------------------------------------------------------*/ void input(){

cout << "Input 9 elements into your 3x3 matrix A: "; for(int i = 0; i < 3; i++) { for(int j = 0; j < 3; j++) { cin >> A[i][j]; // terminates function on failure if(cin.fail()) { cin.clear(); cin.ignore(100, ' '); cerr << " ERROR: Please enter valid input! " << endl; } } } cout << "Input 9 elements into your 3x3 matrix B: "; for(int i = 0; i < 3; i++) { for(int j = 0; j < 3; j++) { cin >> B[i][j]; // terminates function on failure if(cin.fail()) { cin.clear(); cin.ignore(100, ' '); cerr << " ERROR: Please enter valid input! " << endl; } } } } /*------------------------------------------------------- FUNCTON NAME: print PARAMETERS: result RETURN TYPE: will output the results of the array calculation DESCRIPTION: This function will print out the results from the subtraction and addition function -------------------------------------------------------*/ void print(double result[3][3]){ for(int i = 0; i < 3; i++) { cout << "["; for(int j = 0; j < 3; j++) { cout << result[i][j] << "\t"; } cout << "]" << endl; } } /*------------------------------------------------------- FUNCTON NAME: printAB PARAMETERS: RETURN TYPE: DESCRIPTION: This function will simply display the Matrices of A and B right after the user has finished their input -------------------------------------------------------*/ void printAB(){ cout<<" Matrix A :"< for(int i = 0; i < 3; i++) { cout << "["; for(int j = 0; j < 3; j++) { cout << A[i][j] << "\t"; } cout << "]" << endl; }

cout<<" Matrix B :"< for(int i = 0; i < 3; i++) { cout << "["; for(int j = 0; j < 3; j++) { cout << A[i][j] << "\t"; } cout << "]" << endl; } } /*------------------------------------------------------- FUNCTON NAME: addition PARAMETERS: RETURN TYPE: DESCRIPTION: This function will perform the addition and the print function will output the result -------------------------------------------------------*/ void addition(){ for(int i = 0; i < 3; i++) { for(int j = 0; j < 3; j++) { result[i][j] = A[i][j] + B[i][j]; } } print(result); } /*------------------------------------------------------- FUNCTON NAME: subtraction PARAMETERS: RETURN TYPE: DESCRIPTION: This function will perform the subtraction and the print function will output the result -------------------------------------------------------*/ void subtraction(){ for(int i = 0; i < 3; i++) { for(int j = 0; j < 3; j++) { result[i][j] = A[i][j] - B[i][j]; } } print(result); } /*------------------------------------------------------- FUNCTON NAME: determinant PARAMETERS: RETURN TYPE: determin, an integer DESCRIPTION: This function will find the determinant -------------------------------------------------------*/ int determinant(){ int determin = 0; //finding the determinant for(int i = 0; i < 3; i++) determin = determin + (A[0][i] * (A[1][(i+1)%3] * A[2][(i+2)%3] - A[1][(i+2)%3] * A[2][(i+1)%3])); return determin; } /*------------------------------------------------------- FUNCTON NAME: inverse PARAMETERS: RETURN TYPE: DESCRIPTION: This function will find the inverse and output the result -------------------------------------------------------*/ void inverse(){ cout <<" Inverse of Matrix A is: "; cout << " " << endl; for(int i = 0; i < 3; i++){ for(int j = 0; j < 3; j++) cout<< "[" << ((A[(j+1)%3][(i+1)%3] * A[(j+2)%3][(i+2)%3]) - (A[(j+1)%3][(i+2)%3] * A[(j+2)%3][(i+1)%3]))/ determinant()<< "]" << "\t"; cout<<" "; } } }; //Main function int main() { //Initializing Variables; "choice" will initiate a a loop, "input" will come in useful to do a switch statement, and obj will simply create another instance of the original class that can be manipulated bool choice; char input; Matrix obj;

cout << " When filling up matrices, separate individual elements by a space (e.g 2 4 1.4 56.3 ...) ";

obj.input(); obj.printAB(); //Displaying a menu, so that the user can choose what he wants to do choice = false; //The Loop while(!choice) { cout << " " << endl; cout <<"** Choose from the following **"<< endl; cout << " " << endl; cout << "a - Addition" << endl; cout << "s - Subtraction" << endl; cout << "d - Determinant" << endl; cout << "i - Inverse" << endl; cout << "q - Quit" << endl; cout << " " << endl; cout << "Note: Choosing 'i' or 'd' will only apply to Matrix A" << endl; cout << " " << endl; cout << "Enter your choice: "; cin >> input; cout << endl; //A switch to handle the user inputs switch(input){ case 'a': case 'A': obj.addition(); break; case 's': case 'S': obj.subtraction(); break; case 'd'|'D': cout<<"Determinant is : "< cout << " " << endl; break; case 'i': case 'I': obj.inverse(); break; case 'q': case 'Q': exit(0); default:cout<<" ERROR: Please enter valid input! "; }

}

return 0; }