Function floor() in C++
floor Function of cmath Header File in C++
On this page we will discuss about function floor() which is used in C++. The cmath header file is a C++ standard library header file that contains a set of math functions and macro definitions that are used to perform mathematical operations. The floor function is used to calculate the greatest integer that is less than or equal to a given number.
floor() Function in C++
In C++ programming language the floor function is included in cmath header file.
The floor function can handle values of any finite or infinite magnitude within the range of the double type in C++. The datatype of parameter can be double/ float/ long double only.
Note:
If you try to pass a value outside of the range of the double type to floor, the behavior is undefined and may lead to unexpected results or a runtime error.
Declaration of floor function
double floor(double x)
Parameters of floor function
The round function takes a single parameter x.
| Parameter | Description |
|---|---|
| x | It is the number for which you want to calculate the floor. |
Return value of floor function
The floor function in C++ returns the greatest integer that is less than or equal to a given number. The return value is of type double, even if the input is an integer.
Implementation of floor function in C++
Example 1:
The following code shows the use of floor function.
Run
#include
#include
using namespace std;
int main() {
// Initialization of different parameters
double x = 3.14;
cout << "floor of " << x << " is " << floor(x) << endl;
x = -3.14;
cout << "floor of " << x << " is " << floor(x) << endl;
x = 3.9;
cout << "floor of " << x << " is " << floor(x) << endl;
x = -3.9;
cout << "floor of " << x << " is " << floor(x) << endl;
x = 3.0;
cout << "floor of " << x << " is " << floor(x) << endl;
x = -3.0;
cout << "floor of " << x << " is " << floor(x) << endl;
return 0;
}
Output:
floor of 3.14 is 3 floor of -3.14 is -4 floor of 3.9 is 3 floor of -3.9 is -4 floor of 3 is 3 floor of -3 is -3
If the input number is already an integer, the result will be the same as the input. If the input number is negative, the result will be the next smallest integer as seen in above example.
Example 2:
Run
#include <iostream>
#include <cmath>
using namespace std;
int main() {
double result;
// Initializing parameter x
int x = 20;
result = floor(x);
cout << "Floor of " << x << " = " << result;
return 0;
}
Output:
Floor of 20 = 20
Note:
The floor function only works with real numbers. If you try to pass an integer or other type of value to floor, you may need to cast it to a double first.
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