scanf is skipped

I have the following code and I have defined the functions that I am calling here, the problem here is : I run the code input: 1 input: 2 input: 2 input: 6 input: 5 6 // for the scanf associated with i=6; after this I get the output on the screen as enter ur choice and then it exit开发者_开发知识库s out of the program ... its like the scanf gets the value from somewhere but I dunno from where I also tried fflush(stdin) doesnt seem to work can any one please help

int main()
{

  int i,*j,k,pos,val;
  Element *stacka = new Element;

  stacka =NULL;

  while(i!=5)
  {

    printf("Enter ur choice \n");
    fflush(stdin);
    scanf("%d",&i);

    if(i==1)
    {
      if(createStack(&stacka))
      {
        printf("yes");

      }
    }

    if(i==2)
    {
      k=2; 
      if(push(&stacka,&j))
      {
        printf("yes");

      }
    }

    if(i==3)
    {
      if(pop(&stacka,&k))
      {

        printf("yes %d",k);


      }
    }

    if(i==4)
    {
      if(emptyStack(&stacka))
      {
        printf("yes");

      }
    }

    if(i==6)
    {
      scanf("%d,%d",&pos,&val);
      fflush(stdin);
      insert_at_pos(pos,val,&stacka);

    }

  }
return 0;
}

Try inserting a space before %d:

scanf(" %d,%d",&pos,&val);

This will eat any leading whitespace that might be in the input buffer, e.g., the newline from the earlier entry of i.

Also, initialize i before the loop.