how to check whether a linked list is circular.
Answers were Sorted based on User's Feedback
Answer / coder_1
Create two pointers, each set to the start of the list.
Update each as follows:
while (pointer1) {
pointer1 = pointer1->next;
pointer2 = pointer2->next; if (pointer2)
pointer2=pointer2->next;
if (pointer1 == pointer2) {
print (\"circular\n\");
}
}
If a list is circular, at some point pointer2 will wrap
around and be either at the item just before pointer1, or
the item before that. Either way, it?s either 1 or 2 jumps
until they meet.
| Is This Answer Correct ? | 86 Yes | 34 No |
Answer / pratyu
node *ptr1,*ptr2;
ptr1=head;
ptr2=head->next;
while(ptr2)
{
if(ptr1==ptr2)
printf("circular linked list");
ptr2=ptr2->next;
}
printf("not a circular linked list");
| Is This Answer Correct ? | 31 Yes | 7 No |
Answer / priya
This is the function to check if the linklist is circular:
bool CLinklist::ifcircular()
{
node *ptr1,*ptr2;
ptr1 = front;
ptr2 = front;
while(ptr1)
{
ptr1 = ptr1->link;
ptr2 = ptr2->link;
if(ptr2)
ptr2 = ptr2->link;
if(ptr1 == ptr2)
return 1;
}
}
| Is This Answer Correct ? | 15 Yes | 7 No |
consider home pointer as the starting pointer of the linked
list.
consider temp as the temporary pointer.
temp = home;
while(temp != NULL)
{
if(temp -> next == start)
{
flag = 1;
break;
}
else
flag = 0;
temp = temp -> next;
}
if(flag == 1)
printf("Circular");
else
printf("Not circular");
| Is This Answer Correct ? | 30 Yes | 30 No |
Answer / nirwal
hi All
specialy the two pointer solution techies
what about the loop in the link list ?
how you differentiate b/w circular list and list having the
loop?
Think again...........
| Is This Answer Correct ? | 4 Yes | 4 No |
Answer / abhi
while(q->next->next=NULL)
{
p=p->next;
q=q->next->next;
if(p==q)
{
printf("loof is find");
break;
}
}
| Is This Answer Correct ? | 2 Yes | 2 No |
Answer / shahid khan abbasi
bool hasCircle(List l)
{
Iterator i = l.begin(), j = l.begin();
while (true) {
// increment the iterators, if either is at the end,
you're done, no circle
if (i.hasNext()) i = i.next(); else return false;
// second iterator is travelling twice as fast as first
if (j.hasNext()) j = j.next(); else return false;
if (j.hasNext()) j = j.next(); else return false;
// this should be whatever test shows that the two
// iterators are pointing at the same place
if (i.getObject() == j.getObject()) {
return true;
}
}
}
| Is This Answer Correct ? | 2 Yes | 3 No |
Answer / burmeselady
start from pointer1
check all node's next pointer is null or not starting from
pointer1 until pointer1
if a node next pointer is null=> it is not circular.
else it is circular
| Is This Answer Correct ? | 5 Yes | 7 No |
Answer / ishan
by checking whether link field in the last node contains
the address of the first node.
| Is This Answer Correct ? | 17 Yes | 20 No |
Answer / lohitha
node *ptr1,*ptr2;
ptr1=head;
ptr2=head->next;
while(ptr2)
{
if(ptr1==ptr2)
{
printf("circular linked list");
break;
}
ptr2=ptr2->next;
}
printf("not a circular linked list");
| Is This Answer Correct ? | 3 Yes | 6 No |
void main() { char ch; for(ch=0;ch<=127;ch++) printf(“%c %d \n“, ch, ch); }
int aaa() {printf(“Hi”);} int bbb(){printf(“hello”);} iny ccc(){printf(“bye”);} main() { int ( * ptr[3]) (); ptr[0] = aaa; ptr[1] = bbb; ptr[2] =ccc; ptr[2](); }
What is the output of the program given below main() { signed char i=0; for(;i>=0;i++) ; printf("%d\n",i); }
How to palindrom string in c language?
what will be the output of this program? void main() { int a[]={5,10,15}; int i=0,num; num=a[++i] + ++i +(++i); printf("%d",num); }
What is the main difference between STRUCTURE and UNION?
struct Foo { char *pName; }; main() { struct Foo *obj = malloc(sizeof(struct Foo)); clrscr(); strcpy(obj->pName,"Your Name"); printf("%s", obj->pName); } a. Your Name b. compile error c. Name d. Runtime error
#include<stdio.h> main() { int a[2][2][2] = { {10,2,3,4}, {5,6,7,8} }; int *p,*q; p=&a[2][2][2]; *q=***a; printf("%d..%d",*p,*q); }
main() { int (*functable[2])(char *format, ...) ={printf, scanf}; int i = 100; (*functable[0])("%d", i); (*functable[1])("%d", i); (*functable[1])("%d", i); (*functable[0])("%d", &i); } a. 100, Runtime error. b. 100, Random number, Random number, Random number. c. Compile error d. 100, Random number
union u { union u { int i; int j; }a[10]; int b[10]; }u; main() { printf("\n%d", sizeof(u)); printf(" %d", sizeof(u.a)); // printf("%d", sizeof(u.a[4].i)); } a. 4, 4, 4 b. 40, 4, 4 c. 1, 100, 1 d. 40 400 4
#include<stdio.h> #include<conio.h> void main() { int a=(1,2,3,(1,2,3,4); switch(a) { printf("ans:"); case 1: printf("1");break; case 2: printf("2");break; case 3: printf("1");break; case 4: printf("4");break; printf("end"); } getch(); }
main() { int a[10]; printf("%d",*a+1-*a+3); }