I want to write a C++ function in C#:

the C++ code:

#define deleter "/.:_-";
char code[25]; // SR2342-23422-234234

Code:
int take_mod(char *number,int anz,int position)
{
	int k=0,n=0;

	while (zahl[n]!=0)
	{              
		 k=(int)number[n];
#ifdef blank
		if ((strchr(deleter,k) !=0) || (!isdigit(number[n])))
		{
#ifdef
...