Convert iterator to pointer?

Question

I have a std::vector with n elements. Now I need to pass a pointer to a vector that has the last n-1 elements to a function.

F

Answer 1

A safe version to convert an iterator to a pointer (exactly what that means regardless of the implications) and by safe I mean no worries about having to dereference the iterator and cause possible exceptions / errors due to end() / other situations

#include 
#include 
#include 

int main()
{
    std::vector vec;

    char itPtr[25];
    long long itPtrDec;
    
    std::vector::iterator it = vec.begin();
    memset(&itPtr, 0, 25);
    sprintf(itPtr, "%llu", it);
    itPtrDec = atoll(itPtr);
    printf("it = 0x%X\n", itPtrDec);
    
    vec.push_back(123);
    it = vec.begin();
    memset(&itPtr, 0, 25);
    sprintf(itPtr, "%llu", it);
    itPtrDec = atoll(itPtr);
    printf("it = 0x%X\n", itPtrDec);
}

will print something like

it = 0x0

it = 0x2202E10

It's an incredibly hacky way to do it, but if you need it, it does the job. You will receive some compiler warnings which, if really bothering you, can be removed with #pragma