# Ceil and Floor functions in C++

In mathematics and computer science, the floor and ceiling functions map a real number to the greatest preceding or the least succeeding integer, respectively.

floor(x) : Returns the largest integer that is smaller than or equal to x (i.e : rounds downs the nearest integer).

```// Here x is the floating point value.
// Returns the largest integer smaller
// than or equal to x
double floor(double x)  ```

Examples of Floor:

```Input : 2.5
Output : 2

Input : -2.1
Output : -3

Input : 2.9
Output : 2
```

 `// C++ program to demonstrate floor function ` `#include ` `#include ` `using` `namespace` `std; ` ` `  `// Driver function ` `int` `main() ` `{ ` `    ``// using floor function which return ` `    ``// floor of input value ` `    ``cout << ``"Floor is : "` `<< ``floor``(2.3) << endl; ` `    ``cout << ``"Floor is : "` `<< ``floor``(-2.3) << endl; ` ` `  `    ``return` `0; ` `} `

Output:

```Floor is : 2
Floor is : -3
```

ceil(x) : Returns the smallest integer that is greater than or equal to x (i.e : rounds up the nearest integer).

```// Here x is the floating point value.
// Returns the smallest integer greater
// than or equal to x
double ceiling(double x)  ```

Examples of Ceil:

```Input : 2.5
Output : 3

Input : -2.1
Output : -2

Input : 2.9
Output : 3
```

 `// C++ program to demonstrate ceil function ` `#include ` `#include ` `using` `namespace` `std; ` ` `  `// Driver function ` `int` `main() ` `{ ` `    ``// using ceil function which return ` `    ``// floor of input value ` `    ``cout << ``" Ceil is : "` `<< ``ceil``(2.3) << endl; ` `    ``cout << ``" Ceil is : "` `<< ``ceil``(-2.3) << endl; ` ` `  `    ``return` `0; ` `} `

```Ceil is : 3
Ceil is : -2
```

This article is contributed by Sahil Rajput. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Rated as one of the most sought after skills in the industry, own the basics of coding with our C++ STL Course and master the very concepts by intense problem-solving.

My Personal Notes arrow_drop_up
Article Tags :
Practice Tags :

23

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.