/in/foo.cc: In function 'int main()':
/in/foo.cc:9:17: error: 'gerchar' was not declared in this scope
   while(gerchar()!='\n')
                 ^
/in/foo.cc:7:17: warning: unused variable 'b' [-Wunused-variable]
   char a[10001],b[10001];
                 ^
/in/foo.cc:8:11: warning: unused variable 'j' [-Wunused-variable]
   int i=1,j=1;
           ^