C STL Vectors Get iterator from index

Question

So  I wrote a bunch of code that accesses elements in an stl vector by index    but now I need to copy just a chunk of the vector  It looks like vector insert pos  first  last  is the function I want    except I only have first and last as ints  Is there any nice way I can get an iterator to these values

User · Answer

way mentioned by  dirkgently   v begin     index   nice and fast for vectors    but std  advance  v begin    index   most generic way and for random access iterators works constant time too     EDIT differences in usage     std  vector lt  gt   iterator it     v begin     index      or   std  vector lt  gt   iterator it   v begin    std  advance  it  index      added after  litb notes

User · Answer

Try this   vector lt Type gt   iterator nth   v begin     index

User · Answer

Also  auto it   std  next v begin    index    Update  Needs a C  11x compliant compiler

User · Answer

Actutally std  vector are meant to be used as C tab when needed   C   standard requests that for vector implementation   as far as I know - replacement for array in Wikipedia  For instance it is perfectly legal to do this folowing  according to me   int main      void foo const char      sdt  vector lt char gt  vec  vec push back  h    vec push back  e    vec push back  l    vec push back  l    vec push back  o    vec push back   0     foo  amp vec 0        Of course  either foo must not copy the address passed as a parameter and store it somewhere  or you should ensure in your program to never push any new item in vec  or requesting to change its capacity  Or risk segmentation fault       Therefore in your exemple it leads to   vector insert pos   amp vec first index    amp vec last index

User · Answer

Or you can use std  advance  vector lt int gt   iterator i   L begin    advance i  2

[c++] C++ STL Vectors: Get iterator from index?

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