find index in a vector-help urgent!

[noktalivirgul]

how can i find the index of a certain number in a vector?

[vlad from moscow]

There is special standard algorithm that has name std::find

For example

std::vector<int> v = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

std::cout << std::distance( v.begin(), std::find( v.begin(), v.end(), 5 ) ) << std::endl;

Here is a compiled example

#include <iostream>
#include <iterator>
#include <vector>
#include <algorithm>

int main()
{
   std::vector<int> v = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
 
   std::cout << std::distance( v.begin(), std::find( v.begin(), v.end(), 5 ) ) << std::endl;
}

The output is

4

[noktalivirgul]

my vector is defined so:vector<float>difflist;

can i use this std also for this vector ??

and i am sorting my vector. for example my vector is:

vector<float>difflist;
difflist.push_back(5, 6, 12, 9, 37)

ı sort my vector and it seems so: 5, 6, 9, 12, 37.

now, how can i find the place of nine in orginal vector?

if i use this way:
std::cout << std::distance( v.begin(), std::find( v.begin(), v.end(), 5 ) ) << std::endl;

will it give me 3 or2?

[vlad from moscow]

It will give you 0 because 5 is the first element of your vector after sorting.