Rounding up to the nearest multiple of a number

by

This works for positive numbers, not sure about negative. It only uses integer math.

int roundUp(int numToRound, int multiple)
{
    if (multiple == 0)
        return numToRound;

    int remainder = numToRound % multiple;
    if (remainder == 0)
        return numToRound;

    return numToRound + multiple - remainder;
}

Edit: Here’s a version that works with negative numbers, if by “up” you mean a result that’s always >= the input.

int roundUp(int numToRound, int multiple)
{
    if (multiple == 0)
        return numToRound;

    int remainder = abs(numToRound) % multiple;
    if (remainder == 0)
        return numToRound;

    if (numToRound < 0)
        return -(abs(numToRound) - remainder);
    else
        return numToRound + multiple - remainder;
}

More Related Contents:

  1. How to find number of words in a phrase with spaces removed by checking v. dictionary
  2. Create an algorithm that asks the user for two positive numbers, call them “first” and “last”, and prints the sum of all the numbers between first [closed]
  3. How to implement classic sorting algorithms in modern C++?
  4. Fast bignum square computation
  5. Determine if two rectangles overlap each other?
  6. What is the efficient way to count set bits at a position or lower?
  7. Fast exact bigint factorial
  8. Generating combinations in c++
  9. How to find which elements are in the bag, using Knapsack Algorithm [and not only the bag’s value]?
  10. Magic number in boost::hash_combine
  11. Creating all possible k combinations of n items in C++
  12. How do I calculate the week number given a date?
  13. Where can I get a “useful” C++ binary search algorithm?
  14. How to get a random element from a C++ container?
  15. LRU cache design
  16. c++ sort keeping track of indices [duplicate]
  17. Determining if a number is prime
  18. How to add two numbers without using ++ or + or another arithmetic operator
  19. Are there any better methods to do permutation of string?
  20. Reorder vector using a vector of indices [duplicate]
  21. Set back default floating point print precision in C++
  22. Converting epoch time to “real” date/time
  23. Fastest algorithm for primality test [closed]
  24. What is the safe way to fill multidimensional array using std::fill?
  25. Cut set of a graph, Boost Graph Library
  26. What’s time complexity of this algorithm for finding all combinations?
  27. How to find and replace all occurrences of a substring in a string?
  28. Counting number of bits: How does this line work ? n=n&(n-1); [duplicate]
  29. Good C++ solutions to the “Bring all the zeros to the back of the array” interview challenge
  30. Finding square root without using sqrt function?

Leave a Comment