C++ <valarray> - operator< Function

The C++ <valarray> operator< function is used to compare two valarrays, or a valarray and a value. It returns a new valarray of bool elements containing true if the left-hand side value is less than the right-hand side value, else returns false.

Syntax

template <class T>
  valarray<bool> operator< 
    (const valarray<T>& lhs, const valarray<T>& rhs);
template <class T>
  valarray<bool> operator< 
    (const T& val, const valarray<T>& rhs);
template <class T>
  valarray<bool> operator< 
    (const valarray<T>& lhs, const T& val);

Parameters

`lhs`	Specify left-hand side valarray.
`rhs`	Specify right-hand side valarray.
`val`	Specify a value of type T.

Return Value

Returns a new valarray of bool elements with the result of each of the individual comparisons.

Time Complexity

Depends on library implementation.

Example:

The example below shows the usage of operator< function.

#include <iostream>
#include <valarray>
using namespace std;
 
int main (){
  valarray<int> va1 {10, 20, 30};
  valarray<int> va2 {10, 20, 25};
  valarray<bool> va3, va4;

  //result of va1 < 20 is stored in va3 
  va3 = (va1 < 20);

  cout<<boolalpha;
  cout<<"va3 contains: ";
  for(int i = 0; i < va3.size(); i++)
    cout<<va3[i]<<" ";

  //result of va1 < va2 is stored in va4 
  va4 = (va1 < va2);

  cout<<"\nva4 contains: ";
  for(int i = 0; i < va4.size(); i++)
    cout<<va4[i]<<" ";  
    
  return 0;
}

The output of the above code will be:

va3 contains: true false false 
va4 contains: false false false

❮ C++ <valarray> Library