Easy to confuse some of the math method descriptions

1. Math.Round

Returns a close integer value, which is actually what we call rounding a decimal.

/**   * Returns the nearest parameter of long  */staticlong round (double  a)/**    */static int round (float a) 

Examples are as follows:

1. Math.Round (8.1): 8
2. Math.Round (8.4): 8
3. Math.Round (8.5): 9
4. Math.Round (8.9): 9
5. Math.Round (-8.1): 8
6. Math.Round (-8.4): 8
7. Math.Round ( -8.5):-8// negative numbers are different from integers. When the first decimal point is less than or equal to 5, carry is carried , so get-8
8. Math.Round (-8.9):-9//when the first decimal place is greater than 5 o'clock, the loft is carried out. 9 is the next integer less than-8, so get-9

2. Math.floor

is actually the double type that returns the maximum integer value that is not greater than the parameter.

/***/staticdouble floor (double  a  )

Examples are as follows:

Math.floor (8.9): 8.0
Math.floor (8.1): 8.0
Math.floor (-8.1): 9.0
Math.floor (-8.9): 9.0

3. Math.ceil

In contrast to Math.floor, the double type that returns the smallest integer value that is not less than the parameter.

/***/staticdouble ceil (double a)  

Examples are as follows:

Math.ceil (8.9): 9.0
Math.ceil (8.1): 9.0
Math.ceil (-8.1): 8.0
Math.ceil (-8.9): 8.0

Easy to confuse some of the math method descriptions