Cannot implicitly convert type 'double' to 'long'
Solution 1
The Math.Pow
method returns a double
, not a long
so you will need to change your code to account for this:
x = (long)(u % Math.Pow(10, m));
This code will cast the double
result from Math.Pow
and assign that value to x
. Keep in mind that you will lose all the precision providided by decimal
(which is a floating-point type and can represent decimal values). Casting to long
will truncate everything after the decimal point.
Solution 2
Math.Pow returns a double.
the Right Hand Side (RHS) of % can only be an integer type.
you need
x = u % (long)Math.Pow(10, m);///<----here
y = u / (long)Math.Pow(10, m);///here
w = v % (long)Math.Pow(10, m);///here
z = v / (long)Math.Pow(10, m);///here
Additionally, You have the possibility of dividing by zero and destroying the universe.
Solution 3
Change types
long x;
long y;
long w;
long z;
to
double x;
double y;
double w;
double z;
Or make use of
Convert.ToInt64
Solution 4
Math.Pow returns a double. You could explicitly cast to long, for example
x = u % (long)Math.Pow(10, m);
although that is likely not the correct solution. Are you certain that the results that you are after can be properly expressed as a double? If not then change the variables to be declared as doubles rather than longs.
Solution 5
You cant' cast implicitly double to long, use (long) cast or change type of variable declaration to double.
Comments
-
Arash almost 2 years
In this code i got the above error in lines i commented.
public double bigzarb(long u, long v) { double n; long x; long y; long w; long z; string[] i = textBox7.Text.Split(','); long[] nums = new long[i.Length]; for (int counter = 0; counter < i.Length; counter++) { nums[counter] = Convert.ToInt32(i[counter]); } u = nums[0]; int firstdigits = Convert.ToInt32(Math.Floor(Math.Log10(u) + 1)); v = nums[1]; int seconddigits = Convert.ToInt32(Math.Floor(Math.Log10(v) + 1)); if (firstdigits >= seconddigits) { n = firstdigits; } else { n = seconddigits; } if (u == 0 || v == 0) { MessageBox.Show("the Multiply is 0"); } int intn = Convert.ToInt32(n); if (intn <= 3) { long uv = u * v; string struv = uv.ToString(); MessageBox.Show(struv); return uv; } else { int m =Convert.ToInt32(Math.Floor(n / 2)); x = u % Math.Pow(10, m); // here y = u / Math.Pow(10, m); // here w = v % Math.Pow(10, m); // here z = v / Math.Pow(10, m); // here long result = bigzarb(x, w) * Math.Pow(10, m) + (bigzarb(x, w) + bigzarb(w, y)) * Math.Pow(10, m) + bigzarb(y, z);///here textBox1.Text = result.ToString(); return result; } }
Whats is the problem? Thanks!