#include <iostream>
/*
roundUp(n, multiple)
--------------------
Rounds the integer n *up* to the nearest multiple of `multiple`.
Mathematically:
result = ceil(n / multiple) * multiple
We use integer arithmetic for efficiency:
(n + multiple - 1) / multiple → smallest integer ≥ n/m
*/
int roundUp(int n, int multiple) {
if (multiple <= 0) {
// Defensive programming: avoid undefined behavior.
// In real-world code, you'd throw or handle this differently.
return n;
}
// Efficient integer rounding up:
return ((n + multiple - 1) / multiple) * multiple;
}
int main() {
std::cout << "roundUp(53, 20) = " << roundUp(53, 20) << "\n";
std::cout << "roundUp(68, 30) = " << roundUp(68, 30) << "\n";
std::cout << "roundUp(7, 100) = " << roundUp(7, 100) << "\n";
std::cout << "roundUp(119, 100) = " << roundUp(119, 100) << "\n";
std::cout << "roundUp(781, 100) = " << roundUp(781, 100) << "\n";
std::cout << "roundUp(1026, 100) = " << roundUp(1026, 100) << "\n";
std::cout << "roundUp(11689, 1000) = " << roundUp(11689, 1000) << "\n";
}
/*
run:
roundUp(53, 20) = 60
roundUp(68, 30) = 90
roundUp(7, 100) = 100
roundUp(119, 100) = 200
roundUp(781, 100) = 800
roundUp(1026, 100) = 1100
roundUp(11689, 100) = 12000
*/
