ceil()

Published Jul 16, 2021Updated Jul 31, 2023
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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";
}

This results in the following output:

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

Codebyte Example

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

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