C++ ceil()

The ceil() function returns the next whole number that is greater than or equal to the argument.

Syntax

std::ceil(n);

Argument must be a double/float/long double, and the return value will be same type.

Example

Use ceil() to round up some math constants:

#include <iostream>
#include <cmath>

int main() {
  double pi = M_PI;
  double e = M_E
  double a;
  double b;

  a = std::ceil(pi);
  b = std::ceil(e);

  std::cout << "Pi rounded up is " << a << "!\n";
  std::cout << "e rounded up is " << b << "!\n";
}

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This results in the following output:

Pi rounded up is 4!
e rounded up is 3!

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Codebyte Example

Use ceil() function to round up the double 12.3456:

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