코딩을해봤는데

10개의 정수입력 = 1,2,3,4,5,6,7,8,9,10

이순서대로 입력할경우

평균, 최대, 최소 모두 10이 나와버리네

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새로운구문 추가없이 기존구문만 사용해야되

#include <stdio.h>
int main(void)
{
           int i;
           int counter;
           int grade;
           int total;
           int average;
           int highest=0;
           int lowest=1000;

           total = 0;
           counter = 1;

           while (counter <= 10 ) {
                  for(i = 0; i < 10; i++){
                      printf("Grade of student %d:", i+1);
                      scanf("%d", &grade);
               }
               for(i = 0; i < 10; i++){
                     if(grade > highest) highest = grade ;
             if(grade < lowest) lowest = grade ;
            total = total + grade;
            counter = counter + 1;
            }
           }
           average = total / 10;

           printf( "Average Score %d\\n", average );
           printf( "Highest Score %d\\n", highest );
           printf( "Lowest Score %d\\n", lowest );

           return 0;
}

이렇게 출력되야하는데..
횽들 알려줘!