/in/foo.c: In function 'main':
/in/foo.c:7:2: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  if(n=1) s=1;
  ^~
/in/foo.c:8:2: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  else if(n=2) s=2;
  ^~~~