/in/foo.cc: In function 'int main()':
/in/foo.cc:10:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<a.size();)
                 ~^~~~~~~~~
/in/foo.cc:12:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(j=i;j<i+b.size()&&j<a.size();j++)
                 ~^~~~~~~~~~~
/in/foo.cc:12:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(j=i;j<i+b.size()&&j<a.size();j++)
                               ~^~~~~~~~~
/in/foo.cc:20:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(j==i+b.size()-1)
            ~^~~~~~~~~~~~~~
/in/foo.cc:30:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<a.size();)
                 ~^~~~~~~~~
/in/foo.cc:40:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int q=0;q<c.size();q++)
                         ~^~~~~~~~~