C++ ceil()

C++ ceil() returns ceiling value of given number. Ceiling value is the smallest integer value greater than the given number.

Syntax

The syntax of C++ ceil() is

ceil(x)

where

ParameterDescription
xA double, float, long double, or integral type value.

Returns

The return value depends on the type of value passed for parameter x. The return value of ceil(x) is

  • double if x is double or integral type.
  • float if x is float.
  • long double if x is long double.

The synopsis of ceil() function is

double ceil(double x);
float ceil(float x);
long double ceil(long double x);
double ceil(T x); // where T is integral type

ceil() is a function of cmath library. Include cmath library at the start of program, if using ceil() function.

Example

In this example, we read a double value from user into x, and find its ceiling value using ceil() function.

C++ Program

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

int main() {
    double x;
    cout << "Enter a value : ";
    cin >> x;
    
    double result = ceil(x);
    cout << "ceil(" << x << ") : " << result << endl;
}

Output

Enter a value : 3.14
ceil(3.14) : 4
Program ended with exit code: 0
Enter a value : 4.896
ceil(4.896) : 5
Program ended with exit code: 0

Conclusion

In this C++ Tutorial, we learned the syntax of C++ ceil(), and how to use this function to find the ceiling value of given number, with the help of examples.