min_element

Returns the element with the smallest value

Definition

The min_element() algorithm is defined in the standard header <algorithm> and in the nonstandard backward-compatibility header <algo.h>.

Interface

#include <algorithm>
template < class ForwardIterator >
   ForwardIterator min_element(
      ForwardIterator first, 
      ForwardIterator last
   );
template < class ForwardIterator, class BinaryPredicate >
   ForwardIterator min_element(
      ForwardIterator first, 
      ForwardIterator last,
      BinaryPredicate comp
   );

Parameters:

Parameter	Description
first	A forward iterator addressing the position of the first element in the range to be searched for the smallest element
last	A forward iterator addressing the position one past the final element in the range to be searched for the smallest element
comp	User-defined predicate function object that defines the sense in which one element is greater than another. The binary predicate takes two arguments and should return `true` when the first element is less than the second element and `false` otherwise

Description

Min_element finds the smallest element in the range [first, last).

The first version compares objects using operator< and the second compares objects using a function object comp.

Return Value

Returns the lowest element in the range [first, last).

Complexity

The complexity is linear; performs exactly (last - first) - 1 comparisons.

References

Example 1

Problem

This program illustrates the use of the STL min_element() algorithm (default version) to find the minimum value in a vector of integers.

Workings

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

using namespace std;

int main()
{
  int a[] = {8, 6, 10, 2, 4};
  vector<int> v(a, a+5);

  cout <<"\nHere are the integer values in the vector:\n";
  for (vector<int>::size_type i=0; i<v.size(); i++)
    cout <<v.at(i)<<" ";

  cout <<"\nThe minimum value in the vector is "
       <<*min_element(v.begin(), v.end())<<".";

  return 0;
}

Solution

Output:

Here are the integer values in the vector:
8 6 10 2 4

The minimum value in the vector is 2.

References

http://www.smu.ca/academic/science/compsci/

Example 2

Problem

This program illustrates the use of the STL min_element() algorithm (extended version) to find the minimum value in a vector of integers, when one integer is larger than another if and only if it has a greater digit sum.

Workings

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

using namespace std;


/* Tests if one integer has a smaller digit sum than another.
   i1 and i2 have been initialized and i1, i2 are both > 0.
   Returns true if sum of the digits in i1 is < sum of digits in i2, and otherwise returns false. */

bool hasSmallerDigitSum(int i1, int i2)
{
  int digitSum1 = 0;
  while (i1 != 0)
  {
    digitSum1 += i1 % 10;
    i1 /= 10;
  }
  int digitSum2 = 0;
  while (i2 != 0)
  {
    digitSum2 += i2 % 10;
    i2 /= 10;
  }
  return digitSum1 < digitSum2;
}

int main()
{
  int a[] = {39, 49, 110, 81, 47};
  vector<int> v(a, a+5);

  cout << "\nHere are the integer values in the vector:\n";
  for (vector<int>::size_type i=0; i<v.size(); i++)
    cout <<v.at(i)<<" ";

  cout <<"\nThe minimum value (the value with the smallest digit sum) is "
       <<*min_element(v.begin(), v.end(), hasSmallerDigitSum)<<".";

  return 0;
}

Solution

Output:

Here are the integer values in the vector:
39 49 110 81 47

The minimum value (the value with the smallest digit sum) is 110.

References

http://www.smu.ca/academic/science/compsci/

Definition

Interface

Description

Return Value

Complexity

References

Example 1

Example 2

See Also