#include <stdio.h>
#include <stdlib.h>

void print_lematrix(float **lematrix, int dim) {
    int i, j;

    for (j = 0; j < dim; j++) {
        for (i = 0; i < dim + 1; i++)
            printf("%10.4f", lematrix[j][i]);
        printf("\n");
    }
    printf("\n\n");
}

float **allocate_lematrix(int dim) {
    float **A = (float **)malloc(dim * sizeof(float *));
    for (int i = 0; i < dim; ++i) {
        A[i] = (float *)malloc((dim + 1) * sizeof(float));
    }
    return A;
}

void gem(float **A, int n, float *x) {
    int i, j, k;
    float c, sum = 0.0;

    print_lematrix(A, n);


    for (i = 0; i < n - 1; i++) {
        for (j = i + 1; j < n; j++) {
            c = A[j][i] / A[i][i];
            for (k = i; k < n + 1; k++) {
                A[j][k] -= c * A[i][k];
            }
        }
    }

    print_lematrix(A, n);

    for (i = n - 1; i >= 0; i--) {
        sum = 0.0;
        for (j = i + 1; j < n; j++) {
            sum += A[i][j] * x[j];
        }
        x[i] = (A[i][n] - sum) / A[i][i];
    }
}

int main() {
    int i, n;

    n = 3;
    float **A = allocate_lematrix(n);

    float **B = allocate_lematrix(n);
    float *x = (float *)malloc(n * sizeof(float));

    A[0][0] = 1.0;
    A[0][1] = 1.0;
    A[0][2] = 1.0;
    A[0][3] = 9.0;
    A[1][0] = 2.0;
    A[1][1] = -3.0;
    A[1][2] = 4.0;
    A[1][3] = 13.0;
    A[2][0] = 3.0;
    A[2][1] = 4.0;
    A[2][2] = 5.0;
    A[2][3] = 40.0;

    B[0][0] = 10.0;
    B[0][1] = -7.0;
    B[0][2] = 3.0;
    B[0][3] = 5.0;
    B[1][0] = -6.0;
    B[1][1] = 8.0;
    B[1][2] = 4.0;
    B[1][3] = 7.0;
    B[2][0] = 2.0;
    B[2][1] = 6.0;
    B[2][2] = 9.0;
    B[2][3] = -1.0;

    gem(A, n, x);

    printf("\nReseni: \n");
    for (i = 0; i < n; i++) printf("\nx%d=%f", i, x[i]);

    printf("\n\n\n\n\n\n");



    gem(B, n, x);

    printf("\nReseni: \n");
    for (i = 0; i < n; i++) printf("\nx%d=%f", i, x[i]);

    return 0;
}