Write a C program to implement a Generic Linked List

Write a C program to implement a Generic Linked List.
Here is a C program which implements a generic linked list. This is also one of the very popular interview questions thrown around. The
crux of the solution is to use the void C pointer to make it generic. Also notice how we use function pointers to pass the address of
different functions to print the different generic data.

#include "stdio.h"
#include "stdlib.h"
#include "string.h"
typedef struct list {
void *data;
struct list *next;
} List;
struct check {
int i;
char c;
double d;
} chk[] = { { 1, 'a', 1.1 },
{ 2, 'b', 2.2 },
{ 3, 'c', 3.3 } };

void insert(List **, void *, unsigned int);
void print(List *, void (*)(void *));
void printstr(void *);
void printint(void *);
void printchar(void *);
void printcomp(void *);
List *list1, *list2, *list3, *list4;
int main(void)
{
char c[]
= { 'a', 'b', 'c', 'd' };
int i[]
= { 1, 2, 3, 4 };
char *str[] = { "hello1", "hello2", "hello3", "hello4" };
list1 = list2 = list3 = list4 = NULL;
insert(&list1, &c[0], sizeof(char));
insert(&list1, &c[1], sizeof(char));
insert(&list1, &c[2], sizeof(char));
insert(&list1, &c[3], sizeof(char));
insert(&list2, &i[0], sizeof(int));
insert(&list2, &i[1], sizeof(int));
insert(&list2, &i[2], sizeof(int));
insert(&list2, &i[3], sizeof(int));
insert(&list3,str[0],strlen(str[0])+1);
insert(&list3,str[1],strlen(str[0])+1);
insert(&list3,str[2],strlen(str[0])+1);
insert(&list3,str[3],strlen(str[0])+1);
insert(&list4, &chk[0], sizeof chk[0]);
insert(&list4, &chk[1], sizeof chk[1]);
insert(&list4, &chk[2], sizeof chk[2]);
printf("Printing characters:");
print(list1, printchar);
printf(" : done\n\n");
printf("Printing integers:");
print(list2, printint);
printf(" : done\n\n");
printf("Printing strings:");
print(list3, printstr);
printf(" : done\n\n");
printf("Printing composite:");
print(list4, printcomp);
printf(" : done\n");
return 0;
}
void insert(List **p, void *data, unsigned int n)
{
List *temp;
int i;
/* Error check is ignored */
temp = malloc(sizeof(List));
temp->data = malloc(n);
for (i = 0; i <>
*(char *)(temp->data + i) = *(char *)(data + i);
temp->next = *p;
*p = temp;
}
void print(List *p, void (*f)(void *))
{
while (p)
{
(*f)(p->data);
p = p->next;
}
}
void printstr(void *str)
{
printf(" \"%s\"", (char *)str);
}
void printint(void *n)
{
printf(" %d", *(int *)n);
}
void printchar(void *c)
{
printf(" %c", *(char *)c);
}
void printcomp(void *comp)
{
struct check temp = *(struct check *)comp;
printf(" '%d:%c:%f", temp.i, temp.c, temp.d);
}