Summary of the C language Rounding Method

Summary of the C language Rounding Method
The C language has the following methods to take an integer: 1. assign a value directly to an integer variable.Int I = 3.5; or I = (int) 3.5;

This method removes the decimal part.

2. Integer Division operator '/' is an integer division operator.

'/' Itself has the integer/int function. However, the integer division round-robin result is related to the C compiler.

3. Use the floor function

Floor (x) returnsThe maximum integer less than or equal to x. For example:

Floor (3.5) = 3

Floor (-3.5) =-4

4. Use the ceil Function

Ceil (x) returnsMinimum integer greater than x. For example:

Ceil (3.5) = 4

Ceil (-3.5) =-3

Floor () isRound to negative infinity, Floor (-3.5) =-4;

Ceil () isRound to positive infinity, Ceil (-3.5) =-3.

However, in C, the ceil and floor () functions return the double type.

5. rounded up

I found a simple rounded up method on the Internet;

Here we use <> to show the rounded up and [] to show the rounded down. We can prove that:

= [(N-1)/M] + 1 (0 <M <= n m, N, Z)

Without losing its universality, weSet N = Mk + r (0 <= r <M, kε Z),

(1)When r> 0,

Left side: = <(Mk + r)/M> = = K + = K + 1

Right: [(N-1)/M] + 1 = [(Mk + R-1)/M] + 1 = [k + (r-1) /M] + 1 = k + 1 + [(r-1)/M] = k + 1

(2)When r = 0,

Left side: = K

Right side:

[(N-1)/M] + 1 = [(Mk-1)/M] + 1 = [(M (k-1) + M-1)/M] + 1

= [K-1 + (M-1)/M] + 1 = k + [(M-1)/M]

= K

In conclusion, the proposition is proved.

With this formula, we can calculate it in the Code as follows:

Int nn = (N-1)/M + 1

'/' Is rounded down.