total_marks.c

#include<stdio.h>
#include<string.h>

struct Class{
    char name[30];
    char address[50];
};


struct Class student[100];

struct Marks{
    int sub1;
    int sub2;
    int sub3;
    int total;
};

int main(){

    struct Marks student[3] = {{45,67,81,0},{75,53,69,0},{57,36,71,0}};
    struct Marks total = {0,0,0,0};

    for(int i = 0; i <= 2; i++){
        student[i].total = student[i].sub1 + student[i].sub2 + student[i].sub3 ;
        total.sub1 += student[i].sub1;
        total.sub2 += student[i].sub2;
        total.sub3 += student[i].sub3;
        total.total += student[i].total;
    }

    printf("STUDENT          TOTAL\n\n");
    for(int i = 0; i <= 2; i++){
        printf("Student[%d]        %d\n",i+1,student[i].total);
    }

    printf("\n\n\nSUBJECT        TOTAL\n\n");
    printf("%s       %d\n%s       %d\n%s       %d\n","Subject 1",total.sub1,"Subject 2",total.sub2,"Subject 3",total.sub3);

    printf("\nGrand Total = %d\n",total.total);

}