Compilare: main.cpp: In function 'int main()': main.cpp:19:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<s.size();++i) ~^~~~~~~~~ main.cpp:22:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s.size();++i){ ~^~~~~~~~~ main.cpp:23:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(x=0, j=0;j<k && i+j<s.size();++j){ ~~~^~~~~~~~~