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| #include "stdafx.h"
#include <iostream>//i/o
#include <conio.h> //getch
#include <cmath> //fabs, abs
using namespace std;
void ShowVector(int n, double * vec);
void PryamoiHod(int n, double **a, double *b);
void ObratniHod(int n, double **a, double *b, double *x);
int main()
{
int i,j,n;
double **a, *b, *x;
do
{
std::cout<<"Enter NUM of equations: ";
std::cin>>n;
//Выделяем память под матрицу А и векторы В и Х
a = new double *[n];
b = new double [n];
x = new double [n];
for(i = 0; i < n; i++)
{
a[i] = new double[n];
//Ввод a
for(j = 0; j < n; j++)
{
std::cout<<"a["<<i + 1<<"]["<<j + 1<<"] = ";
std::cin>>a[i][j];
}
}
//Ввод b
for(i = 0; i < n; i++)
{
std::cout<<"b["<<i + 1<<"] = ";
std::cin>>b[i];
}
std::cout<<"\tSee input\r\n";
std::cout<<"Matrix A:\r\n";
for(i = 0; i < n; i++)
ShowVector(n, a[i]);
std::cout<<"Vector B:\r\n";
ShowVector(n, b);
std::cout<<"\tSolving on Gauss method\r\n";
PryamoiHod(n, a, b);
std::cout<<"Forvard Gauss course\r\n";//Прямой ход
std::cout<<"Matrix A:\r\n";
for(i = 0; i < n; i++)
ShowVector(n, a[i]);
std::cout<<"Vector B:\r\n";
ShowVector(n, b);
ObratniHod(n, a, b, x);
std::cout<<"Back Gauss course\r\n";//Обратный ход
std::cout<<"Matrix A:\r\n";
for(i = 0; i < n; i++)
ShowVector(n, a[i]);
std::cout<<"Vector B:\r\n";
ShowVector(n, b);
std::cout<<"Results :\r\n";
ShowVector(n, x);
std::cout<<"Press Y for new input\r\n";
//Чистим память
delete [] a;
delete [] b;
delete [] x;
}
while(toupper(getch()) == 'Y');
return 0;
}
void ShowVector(int n, double * vec)
{
for(int i = 0; i < n; i++)
std::cout<<vec[i]<<" ";
std::cout<<endl;
}
void PryamoiHod(int n, double **a, double *b)
{
double v;
for(int k = 0,i,j,im; k < n - 1; k++)
{
im = k;
for(i = k + 1; i < n; i++)
{
if(abs(a[im][k]) < abs(a[i][k]))
{
im = i;
}
}
if(im != k)
{
for(j = 0; j < n; j++)
{
v = a[im][j];
a[im][j] = a[k][j];
a[k][j] = v;
}
v = b[im];
b[im] = b[k];
b[k] = v;
}
for(i = k + 1; i < n; i++)
{
v = 1.0*a[i][k]/a[k][k];
a[i][k] = 0;
b[i] = b[i] - v*b[k];
if(v != 0)
for(j = k + 1; j < n; j++)
{
a[i][j] = a[i][j] - v*a[k][j];
}
}
}
}
void ObratniHod(int n, double **a, double *b, double *x)
{
double s = 0;
x[n - 1] = 1.0*b[n - 1]/a[n - 1][n - 1];
for(int i = n - 2, j; 0 <= i; i--)
{
s = 0;
for(j = i + 1; j < n; j++)
{
s = s+a[i][j]*x[j];
}
x[i] = 1.0*(b[i] - s)/a[i][i];
}
} |
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