Compilare: main.cpp: In function 'void add(nod*, int)': main.cpp:21:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( pos == s.size() ) { ~~~~^~~~~~~~~~~ main.cpp: In function 'bool pop(nod*, int)': main.cpp:32:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( pos == s.size() ) { ~~~~^~~~~~~~~~~ main.cpp: In function 'int count(nod*, int)': main.cpp:47:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( pos == s.size() ) ~~~~^~~~~~~~~~~ main.cpp: In function 'int lp(nod*, int)': main.cpp:53:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( pos == s.size() ) return pos ; ~~~~^~~~~~~~~~~