What's wrong with this program?

[vizard]

I've been trying to learn about pointers and vectors and had to create this program as an exercise in my book. Why doesn't it work (i was supposed to create a vector of ints and then copy the contents into a pointer to a new int[] but that was too challenging so i went with this (i.e. i was supposed to write *pia = new int[] instead of making an array), if you could help me on either question i'd appreciate it.


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

int main ()
{
vector<int> ivec(1);
vector<int>::iterator iter = ivec.begin();
while(cin >> *iter)
{
ivec.push_back(0);
++iter;
}
unsigned int asize = ivec.size();
int p[asize];
int *pp = &p[0];
iter = ivec.begin();
while(iter != ivec.end())
{
*pp = *iter;
pp++;
iter++;
}
unsigned int a = 0;
while(a != asize)
{
cout << *pp << endl;
pp++;
a++;
}
return 0;
}

[WilliamW1979]

You declared p but never used it, then declared *pp and defined it to point to the memory space of p but then later changed that. So I am confused on how you were attempting to do this. Try this:

for(int x=0;x<ivec.size();x++)
{
     p[x] = ivec[x];
}

This will populate your array from your vector. You don't even need the iterators here, save them for maps.