ERROR C2143: Syntax error: missing ';' before '<' C++ - c++

Question

I am having trouble in my C++ code where I have to make a binary heap. It works fine as long as I had the "main" function inside of my "MyHeap.h" file but my professor wants it to run in a separate test file. For some reason the code doesn't want to run whenever I try to put the main function outside of the "MyHeap.h" file. When it runs I get the following error:
error C2143: syntax error: missing';' before '<'
I looked at my code and this is where it says there is an error but I can't see anything.
// MyHeap.h
#ifndef _MYHEAP_H
#define _MYHEAP_H
#include <vector>
#include <iterator>
#include <iostream>
class Heap {
public:
Heap();
~Heap();
void insert(int element);
int deletemax();
void print();
int size() { return heap.size(); }
private:
int left(int parent);
int right(int parent);
int parent(int child);
void heapifyup(int index);
void heapifydown(int index);
private:
vector<int> heap;
};
#endif // _MYHEAP_H
So like I said whenever I have the the int main function right after the private class, it will work just fine. Now when I implement it into my test file which is this:
#include "MyHeap.h"
#include <vector>
#include <iostream>
int main()
{
// Create the heap
Heap* myheap = new Heap();
myheap->insert(25);
myheap->print();
myheap->insert(75);
myheap->print();
myheap->insert(100);
myheap->print();
myheap->deletemax();
myheap->print();
myheap->insert(500);
myheap->print();
return 0;
}
It keeps popping up the errors, any ideas on I could go about fixing this problem so that my code can run from a test file?

Answer 1

Use std::vector instead of vector.
The compiler is complaining it doesn't know about vector.
Since it lives in std namespace, the safest solution is to prefix with std.