islessgreater() in C/C++

In C++, islessgreater() is a predefined function used for mathematical calculations. math.h is the header file required for various mathematical functions.
islessgreater() function is used to check whether the 1st argument given to the function is less than or greater than the 2nd argument given to the function or not. Means if a is the 1st argument and b is the 2nd argument then it check whether a>b || a<b or not.
Syntax:

bool islessgreater(a, b)

CPP

// CPP code to illustrate
// the exception of function
#include <bits/stdc++.h>
using namespace std;

int main()
{
    // Take any values
    int a = 5;
    double f1 = nan("2.0");
    bool result;

    // Since f1 value is NaN so
    // with any value of a, the function
    // always return false(0)
    result = islessgreater(f1, a);
    cout << f1 << " islessgreater than " << a
         << ": " << result;

    return 0;
}

Output: 

nan islessgreater than 5: 0

Example:

• Program:
  
  CPP

  // CPP code to illustrate
  // the use of islessgreater function
  #include <bits/stdc++.h>
  using namespace std;
  
  int main()
  {
      // Take two any values
      float a, b;
      bool result;
      a = 10.2;
      b = 8.5;
  
      // Since 'a' is not less than 'b'
      // but greater than 'b' so answer
      // is true(1)
      result = islessgreater(a, b);
      cout << a << " islessgreater than " << b
           << ": " << result << endl;
  
      int x = 2;
  
      // Since 'x' is not greater than 'b'
      // but less than 'a' variable so answer
      // is true(1)
      result = islessgreater(x, a);
      cout << x << " islessgreater than " << a
           << ": " << result << endl;
  
      a = 8.5;
  
      // Since value of 'a' and 'b' are
      // equal so answer is false(0)
      result = islessgreater(a, b);
      cout << a << " islessgreater than " << b
           << ": " << result;
  
      return 0;
  }

Output:

10.2 islessgreater than 8.5: 1
2 islessgreater than 10.2: 1
8.5 islessgreater than 8.5: 0

Application:
This function can be used in various places, one of them can be in linear search.

CPP

// CPP code to illustrate the
// use of islessgreater function
#include <bits/stdc++.h>
using namespace std;

int main()
{
    // taking inputs
    int arr[] = { 5, 2, 8, 3, 4 };
    int n = sizeof(arr) / sizeof(arr[0]);

    // Lets we want to search for 1 in
    // the arr array
    int a = 1;
    int flag = 0;

    for (int i = 0; i < n; i++)
    {
        if (islessgreater(arr[i], a))
        {
            flag = 1;
        }
    }

    if (flag == 0)
    {
        cout << a << " is present in array";
    }

    else
    {
        cout << a << " is not present in array";
    }
    return 0;
}

Output:

1 is not present in array