# valarray log10() function in C++

• Last Updated : 24 Oct, 2018

The log10() function is defined in valarray header file. This function is used to calculate common logarithm of the value of the elements in valarray.

Syntax:

`log10(varr);`

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

Returns: This function returns a valarray containing the common logarithm of all the elements.

Below programs illustrate the above function:

Example 1:-

 `// C++ program to demonstrate``// example of log10() 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 log10() function``    ``varr1 = ``log10``(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 0.30103 0.477121 0.60206 0.69897
```

Example 2:-

 `// C++ program to demonstrate``// example of log10() function.`` ` `#include ``using` `namespace` `std;``int` `main()``{`` ` `    ``// Initializing valarray``    ``valarray<``double``>``        ``varr = { -1, 6, 3, 45, 5 };`` ` `    ``// Declaring new valarray``    ``valarray<``double``> varr1;`` ` `    ``// use of log10() function``    ``varr1 = ``log10``(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 :
nan 0.778151 0.477121 1.65321 0.69897
```

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