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Index of smallest element in vector in C++

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Aman Saini
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Hello learners, today in this tutorial we will learn about the std::min_element method of the STL library in C++. It is practised for finding the least element in a vector, an array, or in the list. std::min_element returns an iterator pointing to the lowest element in the list. Let’s understand this in more detail using easy and comprehensible examples.

std::min_element is used for finding the least element in a given range [ first, last). By comparing the objects “>”. In the event more than one item is filled with the smallest condition, the iterator returned points to the first of such elements and If the list is empty, it points to the last.

It is defined in the algorithm header file as:

ForwardIterator min_element (ForwardIterator first, ForwardIterator last)

first: It is a forward iterator that points to the beginning of the range of list.

last: It is a forward iterator that points to the end of the range of list.

return value: Returns a pointer pointing to the least value of element.

Using min_element we will find the index of minimum element. Let’s see with an example.

Here is the code:

Example 1: Finding the index of the smallest element is the complete range.

#include <bits/stdc++.h>
using namespace std;

int main(){

    vector<int> myarr = {10, 50, 76, 22, 23, 9, 100, 55, 50};

   // We can also use "auto" instead of  vector<int>::iterator.

    vector<int>::iterator it = min_element(myarr.begin(), myarr.end());

    int minElementIndex = it - myarr.begin();

    cout << "Minimum ELement = " << *it << "\n";

    // add 1 in minElementIndex because vector start from index '0'.

    cout << "Index of Minimum ELement = " << minElementIndex + 1 << std::endl;

    return 0;
}

Output:
Minimum ELement = 9
Index of Minimum ELement = 6

Example 2: Finding the index of the smallest element in a specific range.

#include <bits/stdc++.h>
using namespace std;

int main(){

    vector<int> myarr = {10, 50, 6, 22, 23, 9, 1, 5, 50};

   // Minimum ELement in a specific range of elements

    vector<int>::iterator it = min_element(myarr.begin()+2, myarr.end()-3);

    int minElementIndex = it - myarr.begin();

    cout << "Minimum ELement = " << *it << "\n";

    // add 1 in minElementIndex because vector start from index '0'.

    cout << "Index of Minimum ELement = " << minElementIndex + 1 << std::endl;

    return 0;

}

Output:
Minimum ELement = 6
Index of Minimum ELement = 3

Hope this article was helpful to you. Keep Coding Keep Learning.

C++