c# - rounding decimal to special number of digits -

i need create function rounds decimal numbers this:

round("$32.95", 0) -> $33 round("85.86%", 1) -> 86.9%

where first parameter string , second parameter number of decimal points required

i using math.round converting 85.9

an algorithm can use (i don't know c#):

• get 10-to-the-power(number-of-significant-digits) (=p10)
• multiply decimal-number p10
• add: 0.5
• divide integer-portion of sum (p10) - answer rounded number