/in/foo.cc: In function 'int main()':
/in/foo.cc:27:8: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
 if (j=0) j=len;//注意这里！！！
        ^
/in/foo.cc:48:18: warning: format '%ld' expects argument of type 'long int', but argument 2 has type 'long long int' [-Wformat=]
 printf("%ld",a[i]);
                  ^