Compilare: main.cpp: In function 'int main()': main.cpp:42:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < s.size()){ ~~^~~~~~~~~~ main.cpp:56:17: warning: unused variable 'sum' [-Wunused-variable] int sum = 1; ^~~ main.cpp:72:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < s.size()){ ~~^~~~~~~~~~