# valarray exp() function in C++

• Last Updated : 24 Oct, 2018

The exp() function is defined in valarray header file. This function is used to calculate e raised to the power equal to the value of the element in valarray.

Syntax:

`exp(varr);`

Parameter: This function takes a mandatory parameter varr which represents valarray.

Returns: This function returns a valarray containing the exponential values of all the elements.

Below programs illustrate the above function:

Example 1:-

 `// C++ program to demonstrate``// example of exp() function.`` ` `#include ``using` `namespace` `std;`` ` `int` `main()``{`` ` `    ``// Initializing valarray``    ``valarray<``double``>``        ``varr = { 1, 2, 3, 4, 5 };`` ` `    ``// Declaring new valarray``    ``valarray<``double``> varr1;`` ` `    ``// use of exp() function``    ``varr1 = ``exp``(varr);`` ` `    ``// Displaying new elements value``    ``cout << ``"The new valarray with"``         ``<< ``" manipulated values is : "``         ``<< endl;`` ` `    ``for` `(``double``& x : varr1) {``        ``cout << x << ``" "``;``    ``}`` ` `    ``cout << endl;`` ` `    ``return` `0;``}`

Output:

```The new valarray with manipulated values is :
2.71828 7.38906 20.0855 54.5982 148.413
```

Example 2:-

 `// C++ program to demonstrate``// example of exp() function.`` ` `#include ``using` `namespace` `std;`` ` `int` `main()``{`` ` `    ``// Initializing valarray``    ``valarray<``double``>``        ``varr = { -1, 0, 3, 0, -5 };`` ` `    ``// Declaring new valarray``    ``valarray<``double``> varr1;`` ` `    ``// use of exp() function``    ``varr1 = ``exp``(varr);`` ` `    ``// Displaying new elements value``    ``cout << ``"The new valarray with"``         ``<< ``" manipulated values is : "``         ``<< endl;`` ` `    ``for` `(``double``& x : varr1) {``        ``cout << x << ``" "``;``    ``}`` ` `    ``cout << endl;`` ` `    ``return` `0;``}`

Output:

```The new valarray with manipulated values is :
0.367879 1 20.0855 1 0.00673795
```

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