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determinant.cpp

#include <iostream>
#include <ctime>
#include <time.h>
#define INTEGER
//#define DECIMAL //you'll have to change the type of an array from int to float
using namespace std;

#ifdef INTEGER
void FillMatrix(int **matrix, const int size){
    for (int i=0; i<size; i++){
        for (int j=0; j<size; j++){
            cin >> matrix[i][j];
        }
    }
}
#endif

#ifdef DECIMAL
void FillMatrix(float **matrix, const int size){
    for (int i=0; i<size; i++){
        for (int j=0; j<size; j++){
            matrix[i][j]=static_cast <float> (rand()) / (static_cast <float> (RAND_MAX/10)); //дробные числа от 0 до 10
        }
    }
}
#endif

void PrintMatrix(int **matrix, const int size){
    for (int i=0; i<size; i++){
        for (int j=0; j<size; j++){
            cout << matrix[i][j] << "\t";
        }
        cout << endl;
    }
}

void clearMemory(int** matrix, int size) { //Функция освобождающая память, выделенную под двумерный динамический массив
    for (int i = 0; i < size; i++) {
        delete[] matrix[i];
    }
    delete [] matrix;
}

long long int NumberOfIterations = 0;
int calcDet(int** matrix, int size){
    int Det=0;
    if (size==1){
        NumberOfIterations++;
        return matrix[0][0];
        return NumberOfIterations;
    }
    else if (size==2){
        NumberOfIterations++;
        return matrix[0][0]*matrix[1][1] - matrix[0][1]*matrix[1][0];
        return NumberOfIterations;
    }

    else{
        int sign = 1;

        int** newMatrix = new int*[size-1];
        for (int s=0; s<size-1; s++) {
            newMatrix[s] = new int[size-1];
        }

        for (int k = 0; k < size; k++){
            int sub_i = 0;
            for (int i = 1; i < size; i++){
                int sub_j = 0;
                for (int j = 0; j < size; j++){
                    if (j == k){
                        continue;
                    }
                    else {
                        newMatrix[sub_i][sub_j] = matrix[i][j];
                        sub_j++;
                        NumberOfIterations++;
                    }
                }
                sub_i++;
            }
            Det += sign * matrix[0][k] * calcDet(newMatrix,size-1);
            sign = -sign;
        }
        clearMemory(newMatrix,size-1);
    }
    return Det;
    return NumberOfIterations;
}

int main(){
    srand(time(NULL));

    clock_t start = clock();

    int size;
    cout << "Размер матрицы:" << endl;
    cin >> size;

    int **matrix = new int *[size];
    for (int i = 0; i < size; i++) {
        matrix[i] = new int [size];
    }

    cout << "Введите элементы матрицы" << endl;
    FillMatrix(matrix,size);
    cout << "\nMatrix = " << endl;
    PrintMatrix(matrix,size);

    cout << endl << "Det(Matrix) = " << calcDet(matrix, size) << endl;

    clearMemory(matrix,size);

    clock_t end = clock();
    double seconds = (double)(end - start) / CLOCKS_PER_SEC;

    cout << endl << "TIME = " << seconds << endl << "Количество итераций = " << NumberOfIterations;
}