int I =(int)num； //This is 123, this is abandoned.

int I = int . prase(num)； //Same as above, this seems to be rounded (I'm not sure about this, you can try)

int f = num/ 1 * 100； //is 3 1

There is another way.

string str=num。 ToString()；

string[] c=str.split(' . ');

int . prase(c[0])； //stands for 123, an integer.

int . prase(c[ 1])； //means 3 1, an integer.