help

Code:

#include<iostream>
using namespace std;
struct node {
	int data;
	struct node* next;
};
struct node* BuildOneTwoThree(){
	struct node* head=NULL;
	struct node* second=NULL;
	struct node* third=NULL;
	head= new struct node,second= new struct node,third= new struct node;
	head->next=second,second->next=third,third->next=NULL;
	head->data=1,head->next->data=2,head->next->next->data=3;
	return head;
};
int counter=0;
int length(struct node* list) {
	if(list!=NULL) {
		counter+=1;
		length(list->next);
	}
	return counter;
}

int main(){
	struct node* list=BuildOneTwoThree();
	cout<<"Length of List: "<<length(list)<<endl;
	system("pause");
	return 0;
}

is there any way not to use a global variable with this recursive function

Code:

int counter=0;
int length(struct node* list) {
	if(list!=NULL) {
		counter++;
		length(list->next);
	}
	return counter;
}

move it inside the function and declare it static.

wow it worked.. thanx.. ^_^

Actually it doesn't

Don't return counter. Return a copy of it and set counter back to 0 before you return from the function. Otherwise any call to that function past the first one will not work as expected.

Static variables are always there, even when they are not needed. Another approach is to add a second parameter with a default value of zero, then use it for counting.

Code:

int length(struct node* list, int counter = 0)
{
	if(list != NULL)
	{
		return length(list -> next, counter + 1);
	}
	else
	{
		return 0;
	}
}