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
CPP
// C++ program to demonstrate floor function#include <iostream>#include <cmath>using namespace std;// Driver functionint 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
CPP
// C++ program to demonstrate ceil function#include <iostream>#include <cmath>using namespace std;// Driver functionint 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
Time Complexity: O(1)
Auxiliary Space: O(1)
Let us see the differences in a tabular form -:
| ceil | floor | |
| 1. | It is used to return the smallest integral value n that is not less than n. | It is used to return the largest integral value n that is not greater than n. |
| 2. | It rounds the n upwards. | It rounds the n downwards. |
| 3. | Its syntax is -: data_type ceil (n); | Its syntax is -: data_type floor (n); |
| 4. | It takes only one parameter that is the value to round up. | It takes only one parameter that is the value to round up. |
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