#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void condition(){
    printf("A real square matrix of order 2n is given. The numbers denote submatrices of order n\n");
    printf(" -------\n");
    printf("| 1 | 2 |\n");
    printf(" ------- \n");
    printf("| 3 | 4 |\n");
    printf(" ------- \n");
    printf("Get a new matrix:\n");
    printf(" -------\n");
    printf("| 4 | 3 |\n");
    printf(" ------- \n");
    printf("| 1 | 2 |\n");
    printf(" -------\n");
}
void outputMatrix(int** mass, int size){
    for (int i = 0; i < size; i++){
        for (int j = 0; j < size; j++) {
            printf( "%d \t", mass[i][j]);
        }
        printf("\n");
    }

}
void swap(int** mass,int size){
    int temp;
    int center;
    center = size / 2;
    for (int i = 0; i < (size - center); i++) {
        for (int j = 0; j < (size - center); j++) {
            temp = mass[j][i];
            mass[j][i] = mass[j + center][i + center];
            mass[j + center][i + center] = temp;
        }
    }
    for (int i = size - 1; i >= center ; i--) {
        for (int j = 0; j < (center); j++) {
            temp = mass[j][i];
            mass[j][i] = mass[j + center][i - center];
            mass[j + center][i - center] = temp;
        }
    }
    printf("The resulting matrix: \n");
    outputMatrix(mass,size);
}
void outputInFile(int** mass,int size){
    char nameOfFile[20];
    puts("Enter the name of the file you want to display data in:\n");
    scanf("%s",nameOfFile);
    strcat(nameOfFile,".txt");
    FILE* out = fopen(nameOfFile, "w+");
    fprintf(out,"%s \n","The resulting matrix: ");
    for(int i = 0; i < size; i++ ){
        for(int j = 0; j < size; j++ ){
            fprintf(out,"%d \t",mass[i][j]);
            }
        fprintf(out,"\n");
        }
    printf("Matrix successfully written to file %s",&nameOfFile);
    fclose(out);
}
int main() {
    int size;
    char nameOfFile[20];
    condition();
    printf("Enter the name of the file from which you want to read the information: \n");
    scanf("%s",nameOfFile);
    strcat(nameOfFile,".txt");
    FILE* in = fopen(nameOfFile, "r+");
    fscanf(in,"%d", &size);
    if (size % 2 == 0) {
        int **mass = (int **) malloc(size * sizeof(int *));
        for (int i = 0; i < size; i++) {
            mass[i] = (int *) malloc(size * sizeof(int));
            for (int j = 0; j < size; j++) {
                fscanf(in, "%d", &mass[i][j]);
            }
        }
        fclose(in);
        printf("The original matrix of order 2n:\n");
        outputMatrix(mass, size);
        swap(mass, size);
        outputInFile(mass, size);
    }else{
        printf("Mistake! Modify the file, it should only contain numbers,\n"
               " and the size of the matrix should be 2n");
    }
}