/in/foo.c: In function 'main':
/in/foo.c:7:6: warning: variable 'x' set but not used [-Wunused-but-set-variable]
  int x,i,sum=1;
      ^
/in/foo.c: In function 'yidong':
/in/foo.c:41:10: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(f==0 &&t==1 || f==1 && t==0)
     ~~~~~^~~~~~
/in/foo.c:43:10: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(f==2 &&t==1 || f==1 && t==2)
     ~~~~~^~~~~~
/in/foo.c:45:10: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(f==0 &&t==2 || f==2 && t==0)
     ~~~~~^~~~~~