std:: valarray class in C++
C++98 introduced a special container called valarray to hold and provide mathematical operations on arrays efficiently.
- It supports element-wise mathematical operations and various forms of generalized subscript operators, slicing and indirect access.
- As compare to vectors, valarrays are efficient in certain mathematical operations than vectors also.
Public member functions in valarray class : 1. apply() :- This function applies the manipulation given in its arguments to all the valarray elements at once and returns a new valarray with manipulated values. 2. sum() :- This function returns the summation of all the elements of valarrays at once.
CPP
#include<iostream>
#include<valarray> // for valarray functions
using namespace std;
int main()
{
valarray< int > varr = { 10, 2, 20, 1, 30 };
valarray< int > varr1 ;
varr1 = varr.apply([]( int x){ return x=x+5;});
cout << "The new valarray with manipulated values is : " ;
for ( int &x: varr1) cout << x << " " ;
cout << endl;
cout << "The sum of old valarray is : " ;
cout << varr.sum() << endl;
cout << "The sum of new valarray is : " ;
cout << varr1.sum() << endl;
return 0;
}
|
Output:
The new valarray with manipulated values is : 15 7 25 6 35
The sum of old valarray is : 63
The sum of new valarray is : 88
Time Complexity: O(n)
Space Complexity: O(n)
3. min() :- This function returns the smallest element of valarray. 4. max() :- This function returns the largest element of valarray.
CPP
#include<iostream>
#include<valarray> // for valarray functions
using namespace std;
int main()
{
valarray< int > varr = { 10, 2, 20, 1, 30 };
cout << "The largest element of valarray is : " ;
cout << varr.max() << endl;
cout << "The smallest element of valarray is : " ;
cout << varr.min() << endl;
return 0;
}
|
Output:
The largest element of valarray is : 30
The smallest element of valarray is : 1
Time Complexity: O(n)
Space Complexity: O(n)
5. shift() :- This function returns the new valarray after shifting elements by the number mentioned in its argument. If the number is positive, left-shift is applied, if number is negative, right-shift is applied. 6. cshift() :- This function returns the new valarray after circularly shifting(rotating) elements by the number mentioned in its argument. If the number is positive, left-circular shift is applied, if number is negative, right-circular shift is applied.
CPP
#include<iostream>
#include<valarray> // for valarray functions
using namespace std;
int main()
{
valarray< int > varr = { 10, 2, 20, 1, 30 };
valarray< int > varr1;
varr1 = varr.shift(2);
cout << "The new valarray after shifting is : " ;
for ( int &x : varr1) cout << x << " " ;
cout << endl;
varr1 = varr.cshift(-3);
cout << "The new valarray after circular shifting is : " ;
for ( int &x : varr1) cout << x << " " ;
cout << endl;
return 0;
}
|
Output:
The new valarray after shifting is : 20 1 30 0 0
The new valarray after circular shifting is : 20 1 30 10 2
Time Complexity: O(n)
Space Complexity: O(n)
7. swap() :- This function swaps one valarray with other.
CPP
#include<iostream>
#include<valarray> // for valarray functions
using namespace std;
int main()
{
valarray< int > varr1 = {1, 2, 3, 4};
valarray< int > varr2 = {2, 4, 6, 8};
cout << "The contents of 1st valarray "
"before swapping are : " ;
for ( int &x : varr1)
cout << x << " " ;
cout << endl;
cout << "The contents of 2nd valarray "
"before swapping are : " ;
for ( int &x : varr2)
cout << x << " " ;
cout << endl;
varr1.swap(varr2);
cout << "The contents of 1st valarray "
"after swapping are : " ;
for ( int &x : varr1)
cout << x << " " ;
cout << endl;
cout << "The contents of 2nd valarray "
"after swapping are : " ;
for ( int &x : varr2)
cout << x << " " ;
cout << endl;
return 0;
}
|
Output:
The contents of 1st valarray before swapping are : 1 2 3 4
The contents of 2nd valarray before swapping are : 2 4 6 8
The contents of 1st valarray after swapping are : 2 4 6 8
The contents of 2nd valarray after swapping are : 1 2 3 4
Time Complexity: O(n)
Space Complexity: O(n)
Last Updated :
01 Feb, 2023
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