How to get position of a certain element in strings vector to use it as an index in ints vector

Question

I am trying to get the index of an element in a vector of strings  to use it as an index in another vector of int type  is this possible    Example    vector  lt string gt  Names  vector  lt int gt  Numbers            condition to check whether the name exists or not if  find Names begin    Names end    old name       Names end                 if yes         cout  lt  lt  Enter the new name   lt  lt  endl          cin  gt  gt  name          replace Names begin    Names end    old name   name           Now I want to get the position of old name in the Names vector  to use it in accessing certain element in Numbers vector  So that I can say   Numbers position    3      or whatever value assigned here    I tried using   vector  lt string gt     const iterator pos  pos    find Names begin    Names end    old name    Numbers pos    3    but obviously this doesn t work since pos is of type string

User · Answer

I am a beginner so here is a beginners answer      The if in the for loop gives i which can then be used      however needed such as Numbers i  in another vector      Most is fluff for examples sake  the for if really says it all   int main    vector lt string gt names  Sara    Harold    Frank    Taylor    Sasha    Seymore    string req name  cout lt  lt  Enter search name    lt  lt   n   cin gt  gt req name      for int i 0  i lt  names size  -1    i            if names i   req name               cout lt  lt  The index number for   lt  lt req name lt  lt   is   lt  lt i lt  lt   n               return 0                    else if names i   req name  amp  amp  i  names size  -1                cout lt  lt  That name is not an element in this vector  lt  lt   n             else               continue

User · Answer

If you want an index  you can use std  find in combination with std  distance   auto it   std  find Names begin    Names end    old name    if  it    Names end           name not in vector   else     auto index   std  distance Names begin    it

User · Answer

To get a position of an element in a vector knowing an iterator pointing to the element  simply subtract v begin   from the iterator   ptrdiff t pos   find Names begin    Names end    old name   - Names begin      Now you need to check pos against Names size   to see if it is out of bounds or not   if pos  gt   Names size            old name  not found     vector iterators behave in ways similar to array pointers  most of what you know about pointer arithmetic can be applied to vector iterators as well   Starting with C  11 you can use std  distance in place of subtraction for both iterators and pointers   ptrdiff t pos   distance Names begin    find Names begin    Names end    old name

[c++] How to get position of a certain element in strings vector, to use it as an index in ints vector?

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