Beginner Java question (int, float)

Question

int cinema,dvd,pc,total; double fractionCinema, fractionOther; fractionCinema=(cinema/total)*100; //percent cinema 

So, when I run the code to display fractionCinema, it just gives me zeros. If I change all ints to paired, then this will give me what I'm looking for. However, I use cinema, a computer, and everything else, and they should display as ints, not decimals. What should I do?

Answer 1

When you divide two ints (e.g. 2/3), Java performs integer division and truncates the decimal part.
Therefore, 2 / 3 == 0 .

You need to force Java to do the double split, discarding either the operand to double .

For instance:

 fractionCinema = (cinema / (double)total) * 100; 

Answer 2

Try this instead:

 int cinema, total; int fractionCinema; fractionCinema = cinema*100 / total; //percent cinema 

For example, if cinema/(double)total is 0.5, then fractionCinema will be 50. And no floating point operations are required; all math is done using integer arithmetic.

Adding

As stated in @ user949300, the code above is rounded to the nearest integer. To round the result “correctly”, use this:

 fractionCinema = (cinema*100 + 50) / total; //percent cinema 

Answer 3

When you split two int s, Java will perform integer division, and the fractional part will be truncated.

You can explicitly specify one of the arguments to double via cinema/(double) total or implicitly use an operation such as cinema*1.0/total

Answer 4

As some people have already noted, Java will automatically cut off any fractional parts when separating integers. Just change the variables from int to double.