java methods theory problems

Question 04

Write some rounding functions

Ans

ceil(x)          x is rounded up to its nearest integer. This integer is returned as a double value.

floor(x)            x is rounded down to its nearest integer. This integer is returned as a double value.

rint(x) x           is rounded up to its nearest integer. If x is equally close to two integers, the even one is returned as a double value.

round(x)              Returns (int)Math.floor(x + 0.5) if x is a float and returns (long)Math.floor(x + 0.5) if x is a double.

Question 05

Give some examples of  rounding functions

Ans

Math.ceil(2.1) returns 3.0

Math.ceil(2.0) returns 2.0

Math.ceil(-2.0) returns -2.0

Math.ceil(-2.1) returns -2.0

Math.floor(2.1) returns 2.0

Math.floor(2.0) returns 2.0

Math.floor(-2.0) returns –2.0

Math.floor(-2.1) returns -4.0

Math.rint(2.1) returns 2.0

Math.rint(-2.0) returns –2.0

Math.rint(-2.1) returns -2.0

Math.rint(2.5) returns 2.0

Math.rint(4.5) returns 4.0

Math.rint(-2.5) returns -2.0

Math.round(2.6f) returns 3 // Returns int

Math.round(2.0) returns 2 // Returns long

Math.round(-2.0f) returns -2 // Returns int

Math.round(-2.6) returns -3 // Returns long

Math.round(-2.4) returns -2

Question 06

What is abs() method

Ans

It covert positive number into negative number

Question 07

Give some example of abs()

Ans

Math.abs(-9)  returns  9

Math.abs(-2.3) returns 2.3