adf

using namespace std;

#include <iostream>
#include <stdio.h>
#include <math.h>
#include <fstream>
#define SIZE 3

struct student_{
  double kor;
  double eng;
  double math;
};

struct student_ calc_average(struct student_* s, int n){
  struct student_ average;
  average.kor = 0;
  average.math = 0;
  average.eng = 0;

  for(int i=0;i<n;i++){
    average.kor = average.kor+s[i].kor;
    average.eng = average.eng+s[i].eng;
    average.math = average.math+s[i].math;
  }

  average.kor = average.kor/(float)n;
  average.eng = average.eng/(float)n;
  average.math = average.math/(float)n;

  return average;
}

struct student_ calc_std(struct student_* s, int n){
  struct student_ std;
  std.kor = 0;
  std.math = 0;
  std.eng = 0;

  struct student_ average;
  average = calc_average(s, n);

  for(int i=0;i<n;i++){
    std.kor = std.kor+(s[i].kor-average.kor)*(s[i].kor-average.kor);
    std.eng = std.eng+(s[i].eng-average.eng)*(s[i].eng-average.eng);
    std.math = std.math+(s[i].math-average.math)*(s[i].math-average.math);
  }

  std.kor = sqrt(std.kor);
  std.eng = sqrt(std.eng);
  std.math = sqrt(std.math);

  return std;
}

int main(void){
  char buff[1024];
  size_t n_size;

  struct student_ s[SIZE];
  char Number[4]="No.";
  char Korean[3]="K";
  char English[3]="E";
  char Math[3]="M";

  int i=0;
  int t=0;

  std::ifstream fin("student.txt");
  if(fin.fail()){
    //DO NOTHING
  }
  else{
    double tKor;
    double tEng;
    double tMath;
    while(fin>>tKor>>tEng>>tMath){

      s[i].kor = tKor;
      s[i].eng = tEng;
      s[i].math = tMath;

      i++;

      if(i>=SIZE){
        break;
      }
    }
  }

  while(i<SIZE){
    int error=0;
    printf("Input Kor Eng Math score of student %d: ",i+1);
    scanf("%lf %lf %lf",&s[i].kor, &s[i].eng, &s[i].math);
    if(s[i].kor<0 || s[i].kor>100){
      error=1;
    }
    if(s[i].eng<0 || s[i].eng>100){
      error=1;
    }
    if(s[i].math<0 || s[i].math>100){
      error=1;
    }
    if(error>1){
      printf("ERROR OCCURED\n");
      continue;
    }
    i++;
  }

  printf("%-8s %8s %8s %8s\n",Number, Korean, English, Math);
  while(t<SIZE){
    printf("%d %2.0lf %2.0lf %2.0lf\n", t+1, s[t].kor, s[t].eng, s[t].math);
    t++;
  }

  struct student_ average;
  average = calc_average(s, SIZE);
  printf("AVERAGE_KOR = %f\n",average.kor);
  printf("AVERAGE_ENG = %f\n",average.eng);
  printf("AVERAGE_MATH = %f\n",average.math);

  struct student_ std;
  std = calc_std(s, SIZE);
  printf("STD_KOR = %f\n",std.kor);
  printf("STD_ENG = %f\n",std.eng);
  printf("STD_MATH = %f\n",std.math);


  t=0;
  ofstream fout("output.txt");

  while(t<SIZE){
    fout << s[t].kor << " " << s[t].eng << " " << s[t].math << endl;
    t++;
  }
  fout << "AVE_KOR AVE_ENG AVE_MATH"<<endl;
  fout << average.kor << " " << average.eng << " " << average.math << endl;
  fout << "STD_KOR STD_ENG STD_MATH"<<endl;
  fout << std.kor << " " << std.eng << " " << std.math << endl;

  fout.close();

  return 0;
}