1. 1.The following is a c code on "prime factors of a number". Any suggestions to optimize the code? It runs for a pretty long time for inputs like 35068499. And i also want the code to take 10 digit numbers as input.

   #include<stdio.h>
   long n;
   void pf();
   void main()
   {
       printf("Enter a number: ");
       scanf("%ld",&n);
       pf(n);
   }
   void pf()
   {
       long i,x;
       while(1)
       {
           if(n%2==0)
           {
               printf("2\n");
               n=n/2;
           }
           else
               break;
       }
       x=3;
       while(x<=n)
       {
           for(i=2;i<x;i++)
           {
               if(x%i==0)
               {
                   goto abc;
               }
           }
           while(1)
           {
               if(n%x==0)
               {
                   printf("%ld\n",x);
                   n=n/x;
               }
               else
                   break;
           }
           abc:
               x=x+2;
       }
   }
   

It runs for a pretty long time for inputs like 35068499. And i also want the code to take 10 digit numbers as input.