Guassian Elimination in C++

About Program

This program can calculate Guassian Elimination of any matrix size. It can solve simultaneous equations, inverse matrices and much more.

	/*28/09/2022 By Eong Koungmeng*/
	#include <iostream>
	#include <vector>
	std::vector<std::vector<float>> GaussianElimination(std::vector<std::vector<float>> matrix)
	{
	int rows = matrix.size();
	int cols = matrix[0].size();
	for (int i = 0; i < rows; i++)
	{
	float coefficient1 = matrix[i][i];
	for (int j = 0; j < cols; j++)
	{
	matrix[i][j] /= coefficient1;
	}
	for (int j = 0; j < rows; j++)
	{
	if (j == i) continue;
	float coefficient2 = matrix[j][i];
	for (int k = 0; k < cols; k++)
	{
	matrix[j][k] -= coefficient2 * matrix[i][k];
	}
	}
	}
	return matrix;
	}
	void PrintMatrix(std::vector<std::vector<float>> matrix)
	{
	for (int i = 0; i < matrix.size(); i++)
	{
	for (int j = 0; j < matrix[0].size(); j++)
	{
	std::cout.width(5); std::cout << matrix[i][j] << " ";
	}
	std::cout << std::endl;
	}
	}
	void PrintSE(std::vector<std::vector<float>> matrix)
	{
	std::cout << "X = ";
	for (int i = 0; i < matrix.size()-1; i++)
	{
	std::cout << matrix[i][matrix[0].size()-1] << ", ";
	}
	std::cout << matrix[matrix.size() - 1][matrix[0].size() - 1];
	std::cout << std::endl;
	}
	void PrintInverse(std::vector<std::vector<float>> matrix)
	{
	std::cout << "The inverse matrix is\n";
	int rows = matrix.size();
	int cols = matrix[0].size();
	for (int i = 0; i < rows; i++)
	{
	for (int j = rows; j < cols; j++)
	{
	std::cout.width(5); std::cout << matrix[i][j] << " ";
	}
	std::cout << std::endl;
	}
	std::cout << std::endl;
	}
	int main()
	{
	std::cout << "Result of simultaneous equations with Gaussian Elimination" << std::endl;
	std::vector<std::vector<float>>(matrixA) = { {1, -4, -2, 21}, {2, 1, 2, 3 }, {3, 2, -1, -2} };
	std::vector<std::vector<float>>(ResultMatrixA) = GaussianElimination(matrixA);
	PrintMatrix(ResultMatrixA);
	PrintSE(ResultMatrixA);
	std::cout << std::endl;
	std::cout << std::endl;
	std::cout << "Result of inverse matrix with Gaussian Elimination" << std::endl;
	std::vector<std::vector<float>>(matrixB) = { {-1, 8, -2, 1, 0, 0}, {-6, 49, -10, 0, 1, 0}, {-4, 34, -5, 0, 0, 1} };
	std::vector<std::vector<float>>(ResultMatrixB) = GaussianElimination(matrixB);
	PrintMatrix(ResultMatrixB);
	PrintInverse(ResultMatrixB);
	std::cin.get();
	}

view raw meng.cpp hosted with ❤ by GitHub

The output