Question

Complete the code(in C) that inserts elements into a list. The list should always be in an ordered state.

#include <stdio.h>
#include <stdlib.h>

/* list of nodes, each with a single integer */
struct element {
struct element *next;
int value;
};

/* protypes for functions defined after main */
struct element *elementalloc(void);
struct element *listinitialize();
struct element *insertelement(struct element *, int);
void printlist(struct element *);

/* main
* Creates an ordered list
* Elements added to the list must be inserted maintaining the list
* in an ordered state
*/
int main() {
struct element *listhead = NULL;
listhead = listinitialize();
for (int i = 3; i < 100; i+=11){
listhead = insertnewelement(listhead, i);
}
printlist(listhead);
}

/* allocate memory for a new list element */
struct element *elementalloc(void) {
return (struct element *)malloc(sizeof(struct element));
}

/* simple list initialization function */
struct element *listinitialize() {
const int numbers[7] = {4, 9, 13, 18, 27, 49, 60};
struct element *newlist = NULL;
struct element *tail = NULL;
struct element *temp = NULL;
for (int i = 0; i < 7; i++) {
if (newlist == NULL) {
newlist = elementalloc();
newlist->next = NULL;
newlist->value = numbers[i];
tail = newlist;
} else {
temp = elementalloc();
temp->value = numbers[i];
temp->next = NULL;
tail->next = temp;
tail = tail->next;
}
}
return newlist;
}

/* function to insert elements into an ordered list */
struct element *insertnewelement(struct element *listhead, int x) {
struct element *newelement;
newelement = elementalloc();

struct element *iter = listhead;
while( ) {

}

return listhead;
}

/* print the list and the respective memory locations in list order */
void printlist(struct element *listhead)
{
while (listhead != NULL) {
printf("Memory: %p contains value: %d\n", listhead, listhead->value);
listhead = listhead->next;
}
}

Answer 1

c code for the insert new element in ordered way:

#include <stdio.h>
#include <stdlib.h>
/* list of nodes, each with a single integer */
struct element {
        struct element *next;
        int value;
};

/* protypes for functions defined after main */
struct element *elementalloc(void);
struct element *listinitialize();
struct element *insertnewelement(struct element *, int);
void printlist(struct element *);


/* main
* Creates an ordered list
* Elements added to the list must be inserted maintaining the list
* in an ordered state
*/
int main() {
        struct element *listhead = NULL;
        listhead = listinitialize();
        for (int i = 3; i < 100; i += 11) {
                listhead = insertnewelement(listhead, i);
        }
        printlist(listhead);
}

/* allocate memory for a new list element */
struct element *elementalloc(void) {
        return (struct element *)malloc(sizeof(struct element));
}

/* simple list initialization function */
struct element *listinitialize() {
        const int numbers[7] = {4, 9, 13, 18, 27, 49, 60};
        struct element *newlist = NULL;
        struct element *tail = NULL;
        struct element *temp = NULL;
        for (int i = 0; i < 7; i++) {
                if (newlist == NULL) {
                        newlist = elementalloc();
                        newlist->next = NULL;
                        newlist->value = numbers[i];
                        tail = newlist;
                } else {
                        temp = elementalloc();
                        temp->value = numbers[i];
                        temp->next = NULL;
                        tail->next = temp;
                        tail = tail->next;
                }
        }
        return newlist;
}

/* function to insert elements into an ordered list */
struct element *insertnewelement(struct element *listhead, int x) {
        struct element *newelement;
        newelement = elementalloc();

        newelement->value = x;

        struct element *iter = listhead;
        struct element *prev = NULL;


        while (iter != NULL && iter->value < x ) {
                prev = iter;
                iter = iter->next;
        }

        if (prev == NULL)
        {
                newelement->next = listhead;
                listhead = newelement;
        }
        else
        {
                prev->next = newelement;
                newelement->next = iter;
        }

        return listhead;
}

/* print the list and the respective memory locations in list order */
void printlist(struct element *listhead)
{
        while (listhead != NULL) {
                printf("Memory: %p contains value: %d\n", listhead, listhead->value);
                listhead = listhead->next;
        }
}

NOTE: if found any doubt/problem in the code let me know in the comment section and please upvote.