http://gall.dcinside.com/programming/228581

heuinging.c

#include <stdio.h>
#define MAX_STDT 5
#define MAX_OBJT 5
/* 3(KOR ENG MATH) -> 5(KOR ENG MATH TOT AVG) */

int main() {
  int i, j, tot, r, score[MAX_STDT][MAX_OBJT], *tmp = 0;
  float avg;
  printf("Enter the score...\n");
  
  for(i=0; i<MAX_STDT; i++) {
    printf("%d: ", i+1);
    scanf("%d %d %d", &score[i][0], &score[i][1], &score[i][2]);
    /* do not use scanf_s. it's an implementation dependent stuff. */
  }
  
  printf("NO KOR ENG MATH TOT AVG RANK\n");
  
  for (i = 0; i < MAX_STDT; ++i) { 
    tot = score[i][0] + score[i][1] + score[i][2]; 
    score[i][3] = tot; 
  }
  
  for(i = 0; i < MAX_STDT; ++i) {
    r = 1;
    for(j = 0; j < MAX_STDT; ++j) {
      if (score[i][3] < score[j][3])
	r++;
    }
    score[i][4] = r;
  }
  
  for (i = 0; i < MAX_STDT; ++i) {
    for (j = 0; j < MAX_STDT; ++j) { /* remove a dupilcated declaration. */
      if (score[j][4] == i+1 && tmp != &score[j][4]) {
	tmp = &score[j][4];         
	tot = score[j][3];
	avg = tot/3.0; 
	printf("%d: %3d %3d %3d %3d %3.2f %d\n", j+1, score[j][0], 
	       score[j][1], score[j][2], score[j][3], avg, score[j][4]);                           
      }
    }
  }
  
  return 0;
}