Write C sharp code for factorial using static variables ?

int fact(int);
void main()
{
int no,a;
console.writeLine("Enter the Number...");
console.readLine("{0}",a);
a=fact(no);
console.WriteLine("Result is{0}",a);

}
int fact(j)
{
int i,f=0;
for(i=0;i<=j;i++)
{
f=f*i;

}
return(f);
}