/in/foo.cc: In function 'int main()':
/in/foo.cc:12:7: warning: unused variable 'x' [-Wunused-variable]
   int x[100000];
       ^
/in/foo.cc:21:17: warning: 'mpos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   a[mpos]=a[mpos]+a[mpos+1];
           ~~~~~~^