How to gauge the pointer in the link list in C++?

Joe Wilson

First ask user to enter some numbers then put them in a link list next ask user to choose the location of the pointer which point a node in link list then gauge (move) the pointer to the beginning of the link list or ask user to choose the number that pointer will be moved in link list

for example:

if user choose number 3 the pointer move left 3 nodes from the location which have been chosen before by user, at last show the data of the node which pointer point after movement .

3 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes12y ago
I've altered the code so that the user can now move the pointer to the left or to the right of the initial position:

#include
#include

using namespace std;

int main()
{
list numbers;
list::iterator pos;
int number, count, start, i, move;
char lr;

cout << "How many numbers are to be added to the linked list? : ";
cin >> count;
cout << "Enter them" << endl;
for(int i = 0; i < count; i++)
{
cout << i + 1 << " : ";
cin >> number;
numbers.push_back(number);
}

cout << endl;

do
{
cout << "Which node do you want to start from (1 to " << count << ") : ";
cin >> start;
}
while(start < 1 || start > count);

pos = numbers.begin();
if (start > 1)
{
for(i = 2; i <= start; i++) pos++;
}

cout << "The number at that position is " << *pos << endl << endl;

do
{
cout << "Do you want to move the pointer to the left or the right (l/r) : ";
cin >> lr;
if (lr == 'L') lr = 'l';
if (lr == 'R') lr = 'r';
}
while (lr != 'l' && lr != 'r');

cout << endl;

if (lr == 'l')
{
do
{
cout << "How many nodes do you want the pointer to be moved (0 to " << start - 1 << ") to the left : ";
cin >> move;
}
while (move < 0 || move > start - 1);

if (move > 0)
{
for(i = 1; i <= move; i++) pos--;
}

cout << "The number at position " << start - move << " is " << *pos << endl;
}
else
{
do
{
cout << "How many nodes do you want the pointer to be moved (0 to " << count - start << ") to the right : ";
cin >> move;
}
while (move < 0 || move > count - start);

if (move > 0)
{
for(i = 1; i <= move; i++) pos++;
}

cout << "The number at position " << start + move << " is " << *pos << endl;
}

return 0;
}
Joe Wilson12y ago
Thank you for your answer by the way, how can i move pointer forward .

for example:

if user choose number 3 the pointer move right 3 nodes from the location which have been chosen before by user, at last show the data of the node which pointer point after movement .
Vulpes12y ago
Try this:

#include
#include
#include

using namespace std;

int main()
{
list numbers;
list::iterator pos;
int number, count, start, i, move;

cout << "How many numbers are to be added to the linked list? : ";
cin >> count;
cout << "Enter them" << endl;
for(int i = 0; i < count; i++)
{
cout << i + 1 << " : ";
cin >> number;
numbers.push_back(number);
}

cout << endl;

do
{
cout << "Which node do you want to start from (1 to " << count << ") : ";
cin >> start;
}
while(start < 1 || start > count);

pos = numbers.begin();
if (start > 1)
{
for(i = 2; i <= start; i++) pos++;
}

cout << "The number at that position is " << *pos << endl << endl;

do
{
cout << "How many positons do you want the pointer to be moved to the left (0 to " << start - 1 << ") : ";
cin >> move;
}
while (move < 0 || move > start - 1);

if (move > 0)
{
for(i = 1; i <= move; i++) pos--;
}

cout << "The number at position " << start - move << " is " << *pos << endl;

return 0;
}