text: #include <stdio.h>
  #include <stdlib.h>
  
  int main()
  {
      char map[10] = { 
          ' ', '.', '\'', ':', '~',
          '*', '=', ' ', '%', '#'
      };
      FILE *finput = fopen("Exer_13_12_input.txt", "r"), *foutput = fopen("Exer_13_12_output.txt", "w");
      if (finput == NULL || foutput == NULL) {
          printf("Can't open file.\n");
          exit(EXIT_FAILURE);
      }
      int numbers[20][30];
      for (int i = 0; i < 20; i++)
          for (int j = 0; j < 30; j++)
              fscanf(finput, "%d", &numbers[i][j]);
      char digits[20][31];
      for (int i = 0; i < 20; i++) {
          for (int j = 0; j < 30; j++)
              digits[i][j] = map[numbers[i][j]];
          digits[i][30] = '\0';
      }
      for (int i = 0; i < 20; i++)
          fprintf(foutput, "%s\n", digits[i]);
      fclose(finput);
      fclose(foutput);
      return 0;
  }