Vector in c++ stl

It looks like you are trying to do this:

Code:

#include<iostream>
#include<vector>
using namespace std;
int main()
{
    vector< vector<long long int> > g;
    for (;;)
    {
        int i;
        cin >> i;
        if (i == -1)
        {
            break;
        }

        g.push_back(vector<long long int>(1, i));
    }
}

no...not this
my requirement is wat i mentioned before...
ofcourse it works well with bounds
but i am not able to leave it unspecified

Originally Posted by dpp

ofcourse it works well with bounds
but i am not able to leave it unspecified

The bounds of g are "unspecified". I merely demonstrated how to push back a vector of size 1 as an element of g because it makes sense in your example. If you insist:

Code:

#include<iostream>
#include<vector>
using namespace std;
int main()
{
    vector< vector<long long int> > g;
    for (;;)
    {
        int i;
        cin >> i;
        if (i == -1)
        {
            break;
        }

        g.push_back(vector<long long int>());
        g.back().push_back(i);
    }
}

but this is not i want

wat i wanted was the code above i posted....
its similar to linked list ...are u able to undersatnd my code...its like that of a linked list...


the code u posted is not wat i require

Originally Posted by dpp

wat i wanted was the code above i posted....
its similar to linked list ...are u able to undersatnd my code...its like that of a linked list...

I specifically wrote both my examples to approximate what I thought you were trying to do in your example. Apparently I thought wrong. What exactly are you trying to do?

If you need a linked list, use std::list instead of std::vector.

From your example it is quite impossible to tell what you "require".

In any case, if the item with some index is not in the vector, you can't access it just like that.

hello annon....
i am just asking whetheri can do it this way........
see it works if i declare it as g(100)
and use g[0]
and i ve succesfully using this method for quite some time.....
i ve been using this for quite a long time...so there s no looking back.....
but wat i want now is g with bound unspecified .....
all i wanted to know whther i can leave the bound unspecified or not

Originally Posted by dpp

but wat i want now is g with bound unspecified .....
all i wanted to know whther i can leave the bound unspecified or not

We have already given you the answer: yes, you can grow the vector dynamically at run time, so you do not need to specify the bounds of the vector when you create it.

Maybe a simpler example with a vector of vectors will help:

Code:

#include <iostream>
#include <vector>

using namespace std;

int main()
{
    vector< vector<int> > v;
    v.push_back(vector<int>());
    v[0].push_back(1);
    v[0].push_back(2);
    v.push_back(vector<int>());
    v[1].push_back(3);

    cout << v[0][0] << endl
        << v[0][1] << endl
        << v[1][0] << endl;
}

s u told at the begining...but i cud not find a way to solve it yet

even this gives the same runtime error

Code:

#include<iostream>
#include<vector>
using namespace std;
int main()
{
    int i,j=0;
    //vector<<int>  g;
      vector < vector<long long int> > g;
   
    while(1)
    {
            j++;
     cin>>i;
     if(i==-1)break;
        g.push_back(vector<long long int>());

     g[j].push_back(i);
     }
     return(0);
}

this is wat u told int the last post

u might run it urself and see if u dont get me

Try this:

Code:

#include<iostream>
#include<vector>
using namespace std;
int main()
{
    int i,j=0;
    //vector<<int>  g;
    vector < vector<long long int> > g;

    while(1)
    {
        cin>>i;
        if(i==-1)break;
        g.push_back(vector<long long int>());

        g[j].push_back(i);
        ++j;
    }
    return(0);
}

Notice that I only increment j after the push back.

thanks it works for a simple example.....
but i shud know wat does this mean

G.push_back(vector<long long int> ());

i have so much to do with this...so ineed to know wat it actually does
plz

You need to push back a vector to g first, then push back a number onto that vector (or, perhaps, push a number onto a vector, then push the vector onto g - both will work, but the former method works ALWAYS, the latter only works when adding all elements to the vector first).

--
Mats

Originally Posted by dpp

hello annon....
i am just asking whetheri can do it this way........
see it works if i declare it as g(100)
and use g[0]
and i ve succesfully using this method for quite some time.....
i ve been using this for quite a long time...so there s no looking back.....
but wat i want now is g with bound unspecified .....
all i wanted to know whther i can leave the bound unspecified or not

<rant>Is there some kind of automatic translator out there that takes as input even the most awful badly written piece of crap and converts it into ordinary readable English? Stuff with no capital letters, punctuation of any kind (except where unnecessary), horrible misspelled words and excessive abreviations, words running together, and nonsensical grammar such as shown above?
I mean one can learn far better English of a cereal packet. Seriously, where do people who write like this come from, and what kind of twisted mayhem goes on inside their heads that would make them think that it is appropriate to write such crap here?
Kids these days...?</rant>

but the same code works diffrent if i scan " j "and push it to the vector

Yog Sothoth!

Go study a tutorial, read a book, or at least describe your problem so these guys can actually help you.

"I mean one can learn far [...]write such crap here?"

I blame SMS messaging.

Soma