컴공 1학년인 학생입니다..

마지막 숙제를 가지고 머리를 앓고 있는데 뭐가 잘못됐는지 원하는 값이 안나오네요.

학점과 평균이 제대로 안나오는데 좀 봐주세요;


#include <stdio.h>
#define all_stu 10

typedef struct {
        int number; /* 0으로 시작 하는 수를 받으면 8진수 인식 때문에 꼼수로 했음; */
        char *name;
        int mid, fin, home;
        float unification;
        char *grade;
} all_sheet;

all_sheet  sheet[all_stu];


void data()
{

}




int main(void)
{
        int i = all_stu;
        int sum1,sum2,sum3;
        float ave1,ave2,ave3;

        sheet[0].number = 61111;
        sheet[0].name = " x x x ";
        sheet[0].mid = 80;
        sheet[0].fin = 60;
        sheet[0].home = 70;


        sheet[1].number = 61112;
        sheet[1].name = " x x x ";
        sheet[1].mid = 10;
        sheet[1].fin = 20;
        sheet[1].home = 30;


        sheet[2].number = 61113;
        sheet[2].name = " x x x";
        sheet[2].mid = 20;
        sheet[2].fin = 30;
        sheet[2].home = 20;


        sheet[3].number = 61114;
        sheet[3].name = " x x x";
        sheet[3].mid = 80;
        sheet[3].fin = 60;
        sheet[3].home = 90;


        sheet[4].number = 61115;
        sheet[4].name = " x x x";
        sheet[4].mid = 50;
        sheet[4].fin = 60;
        sheet[4].home = 90;


        sheet[5].number = 61116;
        sheet[5].name = " x x x ";
        sheet[5].mid = 40;
        sheet[5].fin = 60;
        sheet[5].home = 80;


        sheet[6].number = 61117;
        sheet[6].name = " x  x  x ";
        sheet[6].mid = 60;
        sheet[6].fin = 50;
        sheet[6].home = 80;


        sheet[7].number = 61118;
        sheet[7].name = " x x x ";
        sheet[7].mid = 100;
        sheet[7].fin = 90;
        sheet[7].home = 90;


        sheet[8].number = 61119;
        sheet[8].name = "x  x  x";
        sheet[8].mid = 10;
        sheet[8].fin = 60;
        sheet[8].home = 30;


        sheet[9].number = 61110;
        sheet[9].name = " x  x  x ";
        sheet[9].mid = 90;
        sheet[9].fin = 30;
        sheet[9].home = 70;

        for(i=0;i<10;i++){
                sheet[i].unification = (float)(sheet[i].mid*0.4)+(float)(sheet[i].fin*0.4)+(float)(sheet[i].home*0.2);
        }

        
         //  <<<<-----여기가 문제의 학점 구하기----->>>>
        for(i=0;i<10;i++){
                if(sheet[i].unification >= 95) sheet[i].grade = "A+";
                else if(sheet[i].unification >= 90) sheet[i].grade = "A";
                else if(sheet[i].unification >= 85) sheet[i].grade = "B+";
                else if(sheet[i].unification >= 80) sheet[i].grade = "B";
                else if(sheet[i].unification >= 75) sheet[i].grade = "C+";
                else if(sheet[i].unification >= 70) sheet[i].grade = "C";
                else if(sheet[i].unification >= 65) sheet[i].grade = "D+";
                else if(sheet[i].unification >= 60) sheet[i].grade = "D";
                else sheet[i].grade = "F";
                }        



        printf("=========================================================================n");
        printf("학  번   이      름   중간고사  기말고사   숙  제    통합점수   학점n");
        printf("=========================================================================n");

        for(i = 0;i < all_stu;i++){
                printf("%06d   %10s   %5d     %5d     %5d       %5.0lf    %c n", sheet[i].number, sheet[i].name, sheet[i].mid, sheet[i].fin, sheet[i].home, sheet[i].unification, sheet[i].grade);
                
        }
        printf("=========================================================================n");
        // <------------------------- 여기가 평균 ------------------------->
                for(i=0;i<10;i++){
                sum1 += sheet[i].mid;
        }
        for(i=0;i<10;i++){
                sum2 += sheet[i].fin;
        }
        for(i=0;i<10;i++){
                sum3 += sheet[i].home;
        }
        ave1 = (float)(sum1)/(float)(all_stu);
        ave2 = (float)(sum2)/(float)(all_stu);
        ave3 = (float)(sum3)/(float)(all_stu);
        printf("  평균              %5.0f %5.0f %5.0fn",ave1, ave2, ave3);
        printf("=========================================================================n");

        return 0;


}