Integer Upward rounding algorithm: (x+n-1)/n__ algorithm

Floor indicates that the whole ceiling is rounded down

/* 1, assuming that the variable x and n are two positive integers, we know that the result of x/n this expression is to take floor,

* For example, X is 17,n is 4, then the result is 4. How to write an expression if you want the result to be ceiling.

* For example, X is 17,n is 4, the result is 5;x is 16,n is 4, then the result is 4.

*/

Up Rounding algorithm: (x+n-1)/n

Resolution: (1)/n=x/n+ (x+n-1) (n-1)/n=x/n when the x/n is in perfect use

      (2) When x/n, the remainder must be greater than 1, so (x+n-1)/n<=x/n+ (1+n-1) =x/n+1;

From the Linux C one-stop programming book.