A structure can be nested inside another structure.

#include<stdio.h>

int main()
{
    struct bits
    {
        int i:40;
    }bit;

    printf("%d\n", sizeof(bit));
    return 0;
}

#include<stdio.h>
#include<string.h>
void modify(struct emp*);
struct emp
{
    char name[20];
    int age;
};
int main()
{
    struct emp e = {"Sanjay", 35};
    modify(&e);
    printf("%s %d", e.name, e.age);
    return 0;
}
void modify(struct emp *p)
{
     p ->age=p->age+2;
}

#include<stdio.h>

int main()
{
    struct a
    {
        float category:5;
        char scheme:4;
    };
    printf("size=%d", sizeof(struct a));
    return 0;
}

struct emp
{
    int ecode;
    struct emp *e;
};