Math.round and Math.ceil not working

Question

I am trying to combine users, but I can show that my double is rounded to int. Basically, when I enter 4.4999, it doesn't round to 5.

Any ideas?

Answer 1

Math.ceil() returns the limit value. It cannot change the value of the variable that it takes as an argument, because Java passes arguments by value. Therefore you need to do

 hours = Math.ceil(hours); 

Answer 2

The actual solution is to use double inside the ceil method.

Math.ceil(7 * 50 / 100) will return 3.0 , although the actual value obtained as a result of 7*50/100 Math.ceil(7 * 50 / 100) is 3.5 . This is because, since everything is int , the result of 350/100 itself will be 3 .

If, however, if you give Math.ceil(7 * 50 / 100D) , the result will be 4.0 .

So, 4.999 in your question should be double , and not the result of an integer operation like 4999/1000 .

Just make sure that everything you give inside ceil is double , not int .

Answer 3

Both functions return rounded (or ceiling) values, but do not change the variable passed as a parameter.

Use for example. hours = Math.ceil(hours); .

Answer 4

You do not assign the result of Math.ceil(hours) back to hours , so it will never be rounded.

Answer 5

Math.ciel returns a Double . Something like this should work (inside your hours > 0 block):

 cost += Math.ceil(hours) * hourlyRate; 

Answer 6

 int a = 15 int b = 2; int x = (int) Math.ceil( a / b ); int y = (int) Math.ceil( (double) a / (double) b ); 

results

x: 7

y: 8