****************************************************

        이름              점수                성적

*****************************************************

a                           40

b                           70

c                            88

d                            70

e                            50

f                             90

g                            75

h                            65

i                              95

j                              50

*****************************************************

평균:______점 / 표준편차:____점 / 분산:____점




A 100-90

B  89-80

C  79-70

D  69-60

F  60-

이런 문제의 소스입니다..
//////////////////////////

#include <stdio.h>
#include <math.h>
#define COUNT 10


int Grade(int n)  {
    if(n>=90)
        return 'A';
    else if(n>=80)
        return 'B';
    else if(n>=70)
        return 'C';
    else if(n>=60)
        return 'D';
    else
        return 'F';
}

void main()
{
    int stu[10][3], mark;   

    float sum=0,sum2=0, mean, var, dev;

    for(int i=0;i <COUNT;i++)

   {
        stu[i][0]='a'+i;
        printf("%c 학생 점수...? ", stu[i][0]);
        scanf("%d", &mark);
        sum +=mark;  

        stu[i][1]=mark;  

        stu[i][2]=Grade(mark);
    }
    mean = (float)sum / COUNT;

    for(i=0;i<COUNT;i++)

        sum2 += pow(stu[i][1]-mean, 2);

    dev = sum2 / COUNT;  
    var = (float)sqrt(dev); 
    printf("********************************** \n");
    printf("이름\t점수\t성적\n");
    for(i=0;i        printf("%c \t%d \t%c \n", stu[i][0], stu[i][1], stu[i][2]);
    printf("********************************** \n");
    printf("평균: %3.2f점 / 표준편차: %3.2f점 / 분산: %3.2f점 \n", mean, var, dev);

}





프로그램을 짜봤는데 에러가 떠서요... 어딜 고쳐야 할지 주석좀 부탁드려요...~~