inserting some values in vector?

Question

I write a piece code with C++ and I used vector.insert() and iterator to inserting values in vector. but I received an error:

Vector iterator not incremental

I can not figure out what is wrong with this code. my guess is ++it, but I can not fix the problem. I would appreciate for any help.

#include <iostream>
#include <vector>
using namespace std;

int main(){

    vector<int>::iterator it;
    vector<int> vec2(4);

    it  = vec2.begin();
    vec2.insert(it, 45);
    ++it;  // error pops here                    
    vec2.insert (it,23);

    for(it = vec2.begin(); it!= vec2.end(); ++it)
            cout << " "<<*it<<endl;
return 0;
}

What are you trying to do exactly? What is your desired output - What would you like the resulted vector to **contain**? Maybe you needed the `push_back()` function — Khalil Khalaf, Sep 04 '16 at 22:19
you mean I need new iterator? would you please explain how can I work with insert function. — Rommel, Sep 04 '16 at 22:24

score 0 · Answer 1 · answered Sep 04 '16 at 22:24

You are pretty close. Your error is that insertion invalidates the iterator, so you need to re-assign it:

it = vec2.insert(it, 45);
++it;                      
it = vec2.insert (it,23);

Demo.

Your program prints 45 23 0 0 0 0. The trailing zeros come from the initial set-up of the vector of four values.

inserting some values in vector?

1 Answers1