Compilare: main.cpp: In function 'int main()': main.cpp:67:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<=s.size(); i++) ~^~~~~~~~~~ main.cpp:137:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for (int i=a; i<=b; i++) ^~~ main.cpp:145:9: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' fo << k; ^~