/in/foo.cc: In function 'int main()':
/in/foo.cc:12:9: warning: variable 'a' set but not used [-Wunused-but-set-variable]
     int a[10000];
         ^
/in/foo.cc:6:12: warning: 'need' may be used uninitialized in this function [-Wmaybe-uninitialized]
     cout<<y;
            ^
/in/foo.cc:15:9: note: 'need' was declared here
     int need;
         ^~~~