Trying to restrict math.pow value upto 4 decimal value-CodePudding

I am trying to restrict value up to 4 decimal for Math.Pow((Density * 10), -12)

where double Density = 0; is defined as variable

now if Density=7; then Math.Pow((Density * 10), -12) calculate as 7.22476158090089E-23 but I want it like 7.2247 E-8.

Any idea would be appreciated.

CodePudding user response：

If you want to restrict the decimal precision to 4 decimal places you can use the Exponential Format Specifier, specifying the number of decimals to display "E4":

var answer = Math.Pow(70, -12);
var displayVal = string.Format("{0:E4}", answer);
// output
7.2248E-023

Note that

The exponent always consists of a plus or minus sign and a minimum of three digits.

However, you can use the General Format Specifier which

If scientific notation is used ... The exponent contains a minimum of two digits. This differs from the format for scientific notation that is produced by the exponential format specifier, which includes a minimum of three digits in the exponent.

You will need to use G5 to produce 5 significant digits:

var answer = Math.Pow(70, -12);
var displayVal = string.Format("{0:G5}", answer);
// output
7.2248E-23