Compilare: main.cpp: In function 'bool ok(int)': main.cpp:39:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=len;j<str[i].length();j++) ~^~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:71:16: warning: 'dr' may be used uninitialized in this function [-Wmaybe-uninitialized] mij=(st+dr)/2; ~~~^~~~