/in/foo.c: In function 'Prime':
/in/foo.c:13:2: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  if(i=num)
  ^~
/in/foo.c: In function 'main':
/in/foo.c:24:6: warning: 'num' is used uninitialized in this function [-Wuninitialized]
  int x2=num-x1;
      ^~