 # C++ floor()

The `floor()` function in C++ returns the largest possible integer value which is less than or equal to the given argument.

It is defined in the cmath header file.

### Example

``````#include <iostream>
#include <cmath>
using namespace std;

int main() {

// get the largest possible integer less than or equal to 68.95
cout << floor(68.95);

return 0;
}

// Output: 68``````

# floor() Syntax

The syntax of the `floor()` function is:

``floor(double num);``

## floor() Parameters

The `floor()` function takes the following parameters:

• num - a floating point number whose floor value is computed. It can be of the following types:
• `double`
• `float`
• `long double`

## floor() Return Value

The `floor()` function returns:

• the largest possible integer value which is less than or equal to num

## floor() Prototypes

The prototypes of the `floor()` function as defined in the cmath header file are:

``````double floor(double num);

float floor(float num);

long double floor(long double num);

// for integral types
double floor(T num);``````

## Example 1: C++ floor()

``````#include <iostream>
#include <cmath>
using namespace std;

int main() {
double num, result;

num = 10.25;
result = floor(num);

cout << "Floor of " << num << " = " << result << endl;

num = -34.251;
result = floor(num);

cout << "Floor of " << num << " = " << result << endl;

num = 0.71;
result = floor(num);

cout << "Floor of " << num << " = " << result;

return 0;
}``````

Output

```Floor of 10.25 = 10
Floor of -34.251 = -35
Floor of 0.71 = 0```

## Example 2: C++ floor() for Integral Types

``````#include <iostream>
#include <cmath>
using namespace std;

int main() {
double result;

int num = 15;
result = floor(num);

cout << "Floor of " << num << " = " << result;

return 0;
}``````

Output

`Floor of 15 = 15`

The floor of an integral value is the integral value itself, so the `floor()` function isn't used on integral values in practice.