Problem doing comparisons with fractions

[pstrusi]

Hi Ninjas,

This is simple but I still can't see why.

I'm doing a very simple logic comparison, a double variable against a fraction. For example:

Let's suppose a=0.5, then I do

if ( a>0.4 && a<0.6 )
{
EnterLong(100000, "BUY");
}

under this way the code sends a BUY order, BUT if I do the same comparison like this:

if ( a>4/10 && a<6/10 )
{
EnterLong(100000, "BUY");
}

The code does nothing. Why? and how can I solve it? Despite this problem is easy to solve writing directly, I use a lot fractions, so I´d like to know how.

Thanks

[pstrusi]

I found the solution. Obviously cause the type of variable.

If I do this change, then it does work perfect

if ( a>4.0/10.0 && a<6.0/10.0 )
{
EnterLong(100000, "BUY");
}

[Harry]

I found the solution. Obviously cause the type of variable.

If I do this change, then it does work perfect

if ( a>4.0/10.0 && a<6.0/10.0 )
{
EnterLong(100000, "BUY");
}

Correct. Also see the C# Reference for the division operator.

http://msdn.microsoft.com/en-us/library/3b1ff23f.aspx

"When you divide two integers, the result is always an integer. For example, the result of 7 / 3 is 2. To determine the remainder of 7 / 3, use the remainder operator (%). To obtain a quotient as a rational number or fraction, give the dividend or divisor type float or type double."

Sample results:

7 / 3 = 2
-7 / 3 = -2
7 % 3 = 1
7 / 3.0 = 2.33333333333333
7.0 / 3 = 2.33333333333333
8 / 5 = 1
8 / -5 = -1
8 % 5 = 3
8 / 5.0 = 1.6
8.0 / 5 = 1.6