Matrix Calculator CLI

Project roadmap

1. 01

   Create the Matrix class

   ~1.5h

   Create matrix.h and matrix.cpp with a Matrix class storing its number of rows and columns and its values in a std::vector<double> (row after row). Add a constructor taking the size (filled with zeros), rows() and cols(), and an at(row, col) method that checks the indexes and throws std::out_of_range when they're invalid. Done when: a small program creates a 2×3 matrix, sets values and reads them back.

2. 02

   Read matrices

   ~1.5h

   Write a function that reads a matrix from any input stream: first the number of rows and columns, then the values. Use it both for typing a matrix and for loading one from a file with std::ifstream. Reject bad input (letters, too few values, a size of 0) with a clear message. Done when: matrices can be typed in and loaded from matrices/a.txt.

3. 03

   Add operators

   ~2h

   Overload operator+ and operator- (the sizes must be equal), operator* for two matrices (A's columns must equal B's rows; each result cell is a row of A times a column of B, summed) and operator* for a matrix and a number. When sizes don't fit, throw std::invalid_argument with a message showing both sizes. Done when: A + B and A * B give the results you calculated by hand.

4. 04

   Add transpose and printing

   ~1h

   Add a transpose() method returning a new matrix with rows and columns swapped. Overload operator<< to print a matrix with every column aligned, using std::setw and a fixed number of decimals, for example 2. Done when: a 2×3 matrix transposes to 3×2 and prints in neat columns.

5. 05

   Build the menu

   ~1.5h

   Write main.cpp with a loop menu: load or type matrix A, load or type matrix B, show both, A + B, A - B, A × B, transpose A, multiply A by a number, and quit. Catch exceptions around each operation and show their message without closing the program. Done when: every menu option works, and invalid operations show an error and return to the menu.

6. 06

   Write tests

   ~1.5h

   Write a tests.cpp program using assert (or a small framework like doctest) that checks: addition and multiplication with known results, multiplying by the identity matrix returns the same matrix, transposing twice returns the original, and mismatched sizes throw. Build everything with a Makefile or CMake. Done when: the tests pass, and both programs build with one command.

Resources

• DocsOperator overloading (cppreference)
• Docsstd::vector (cppreference)
• DocsLearn C++: operator overloading
• ArticleMatrix multiplication (Wikipedia)