CalcMath - lab1

#include <conio.h>
#include <stdio.h>
#include <math.h>
#include <memory.h>

int main()
{
	float mSOLE[3][4] = {
		{ 2, 4, -7, 1 },
		{ 3, 6, 1, 0 },
		{ 1, 3, 2, -1 }
	};

	// by columns
	for (int k = 0; k < 2; k++)
	{
		int m = k;

		for (int i = k + 1; i < 3; i++)
		{
			if (fabs(mSOLE[m][k]) < fabs(mSOLE[i][k]))
			{
				m = i;
			}
		}

		float pTmp[4];
		memcpy(pTmp, mSOLE[k], 4 * 4);
		memcpy(mSOLE[k], mSOLE[m], 4 * 4);
		memcpy(mSOLE[m], pTmp, 4 * 4);

		for (int i = k + 1; i < 3; i++)
		{
			float fDivider = -mSOLE[i][k] / mSOLE[k][k];
			for (int j = k; j < 4; j++)
			{
				mSOLE[i][j] += mSOLE[k][j] * fDivider;
			}
		}
	}

	float vRoots[3] = { 0.0f, 0.0f, 0.0f };

	//mSOLE[2][3] /= mSOLE[2][2];
	//mSOLE[2][2] /= mSOLE[2][2];

	for (int i = 2; i >= 0; i--)
	{
		for (int j = 2; j > i; j--)
		{
			vRoots[i] -= mSOLE[i][j] * vRoots[j];
		}

		vRoots[i] += mSOLE[i][3];
		vRoots[i] /= mSOLE[i][i];
	}

	for (int i = 0; i < 3; i++)
		printf("%0.5f ", vRoots[i]);
	printf("\n");

	_getch();
	return 0;
}