/in/foo.cc: In member function 'bignum bignum::operator+(bignum) const':
/in/foo.cc:50:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if(g==0 && k>=b.s.size() && k>=s.size()) {break;}
                        ~^~~~~~~~~~~~
/in/foo.cc:50:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if(g==0 && k>=b.s.size() && k>=s.size()) {break;}
                                         ~^~~~~~~~~~
/in/foo.cc:52:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if(k<b.s.size()) x+=b.s[k];
                ~^~~~~~~~~~~
/in/foo.cc:53:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if(k<s.size()) x+=s[k];
                ~^~~~~~~~~
/in/foo.cc: In member function 'bignum bignum::operator-(bignum) const':
/in/foo.cc:63:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if(g==0 && k>=s.size()) {break;}
                        ~^~~~~~~~~~
/in/foo.cc:65:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if(k<b.s.size()) x-=b.s[k];
                ~^~~~~~~~~~~
/in/foo.cc: In member function 'bignum bignum::operator*(bignum) const':
/in/foo.cc:7:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define siji(i,x,y) for(int i=(x);i<=(y);++i)
                                    ^
/in/foo.cc:76:9: note: in expansion of macro 'siji'
         siji(i,1,s.size()+b.s.size()+2) c.s.push_back(0);
         ^~~~
/in/foo.cc:77:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<s.size();++i) {
                     ~^~~~~~~~~
/in/foo.cc:78:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int j=0;j<b.s.size();++j) {
                         ~^~~~~~~~~~~