#include <stdio.h>

int main(void) {

  FILE *opena;
  FILE *openb;
  FILE *write_sum;

  int mata[10][10], matb[10][10], sum[10][10];

/*mata.txt*/
  opena = fopen("mata.txt", "r");
  if (opena == NULL) {
    printf("Failed to read mata.txt");
    return 0;
  } else {
    for (int i=0; i<10; i++) {
      for (int j=0; j<10; j++) {
         if (j==9) {
          fscanf(opena, "%d\n", &mata[i][j]);
        } else {
          fscanf(opena, "%d ", &mata[i][j]);
        }
      }
    }
  }
  fclose(opena);

  /*matb.txt*/
  openb = fopen("matb.txt", "r");
  if (openb == NULL) {
    printf("Failed to read matb.txt");
    return 0;
  } else {
    for (int i=0; i<10; i++) {
      for (int j=0; j<10; j++) {
        if (j==9) {
          fscanf(opena, "%d\n", &matb[i][j]);
        } else {
          fscanf(opena, "%d ", &matb[i][j]);
        }
      }
    }
  }
  fclose(openb);

   /*sum of mata and matb*/
  for (int i=0; i<10; i++) {
    for (int j=0; j<10; j++) {
      sum[i][j] = mata[i][j] + matb[i][j];
    }
  }

  /*write sum.usr*/
  write_sum = fopen("sum.usr", "w");
  if (write_sum == NULL) {
    printf("Failed to write sum.usr");
    return 0;
  } else {
    for (int i=0; i<10; i++) {
      for (int j=0; j<10; j++) {
        if (j==9) {
          fprintf(write_sum, "%d\n", sum[i][j]);
        } else {
          fprintf(write_sum, "%d ", sum[i][j]);
        }
      }
    }
    printf("The sum of the matrices has been calculated into the file sum.usr.");
  }
  fclose(write_sum);

}