Rounding to nearest .00 or .05 instead of .01 or .02 etc in decimals-CodePudding

I have this rounding where I am trying to round the decimal price so that the decimals always round to either .00 or .05 (using this rule .00,.01,.02,.03,.04 = .00 and .05,.06,.07,.08,.09 = .05) - but right now with the below code it also returns .01, .02 etc in the decimal numbers.

 // 2 is the number of decimals that it should return.
 decimal unitPriceFloored = System.Math.Round(price, 2, System.MidpointRounding.ToZero);

How can I change it so that it round the price to .00 or .05 in the decimals? Just to clarify - this should work the same way with .10 and .15 etc. (all 2 decimal comma numbers)

CodePudding user response：

I don't know of a built-in function to do this. Here's a way:

for(decimal m = 1m; m < 1.2m; m = m   0.01m)
   WriteLine( $"{m} -> {Math.Truncate(m)   (int)(((m - Math.Truncate(m))*100)/5) * 0.05m }");

This prints:

1 -> 1.00 
1.01 -> 1.00
1.02 -> 1.00
1.03 -> 1.00
1.04 -> 1.00
1.05 -> 1.05
1.06 -> 1.05
1.07 -> 1.05
1.08 -> 1.05
1.09 -> 1.05
1.10 -> 1.10
1.11 -> 1.10
1.12 -> 1.10
1.13 -> 1.10
1.14 -> 1.10
1.15 -> 1.15
1.16 -> 1.15
1.17 -> 1.15
1.18 -> 1.15
1.19 -> 1.15

CodePudding user response：

This should work:

decimal  cal   ( decimal d )
{

 decimal num =  d;

decimal or =  digits(  num); 
 
if (or >= .05m)  return (num - or)   .05m ; 
 return   num -or;
}




 decimal  digits   (   decimal  x )
{ while( x >  1000 )
{
    x-=1000; 
}
while ( x >100)
{
     x-=100; 
}
while(x > 10)
{
    x -= 10; 
}
  while (   x   >= 1   )
{
    x--; 
}

return subdigits (x) ; 
}    
decimal subdigits( decimal some)
{


while ( some  >=  0.1m )
{
     some   -=.1m ;
}

return  some ;

}

PS: Still have to get used to stackoverflow formatting,sorry ... Results are the following:
1->1
1.01->1.0
1.02->1
1.03->1
1.04->1

1.05->1.05
1.06->1.05
1.07->1.05
1.08->1.05
1.09->1.05
1.1-<1.1
2->2
Now it should work :D