Compilare: main.cpp: In function 'int main()': main.cpp:30:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < sir1.length(); j++) ~~^~~~~~~~~~~~~~~ main.cpp:35:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < sir2.length(); j++) ~~^~~~~~~~~~~~~~~