My Mandelbrot sketching program in c# isn't working

z = math.add(math.pow(z, 2), c);

if(x = NULL)//assignment - as is, this statement will always evaluate 
            //to false, as x is assigned to NULL.

if(x == NULL)// comparison - this will test whether x is equal to NULL without changing x.

   scanf("%s", &name);//the 'address of' operator: '&' is not needed here.
                      //The symbol 'name' is an array of char, and is
                      //located at the address of the first element of the array.

   scanf("%s", name);//with '&' removed.

   scanf("%24s", name);//'24' will prevent buffer overflows
                       //and guarantee room for NULL termination. 

char buffer[25];//create an additional buffer
...
memset(name, 0, 25);//useful in loops (when used) to ensure clean buffers
memset(buffer, 0, 25);
fgets(buffer, 24, stdin);//replace scanf with fgets...
sscanf(buffer, "%24s", name);//..., then analyze input using sscanf 
                             //and its expansive list of format specifiers 
                             //to handle a wide variety of user input.
                             //In this example, '24' is used to guard 
                             //against buffer overflow.

if (currentstate == you_win){
        System.out.println("'X' Won!!");
        else if (currentstate == comp_win)
            System.out.println("'O' won!!");
            else if (currentstate == draw)
            System.out.println("It's a Draw :(");
    }

    if (currentstate == you_win){
        else if (currentstate == comp_win)
            //...
    }

if (currentstate == you_win){
      // ...
 }
 else if (currentstate == comp_win) {
     // ...
  }
    //...

switch (currentstate) {
       case you_win:
             System.out.println("'X' Won!!");
             break;
        case comp_win:
            System.out.println("'O' won!!");
            break;

        case draw:
            System.out.println("It's a Draw :(");
            break;
}