Compilare: main.cpp: In function 'void calcul()': main.cpp:21:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < a.length()) ~~^~~~~~~~~~~~ main.cpp: In function 'void ans()': main.cpp:41:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < b.length()) ~~^~~~~~~~~~~~ main.cpp:48:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == a.length()) ~~^~~~~~~~~~~~~ main.cpp:53:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i < b.length() && b[i] != a[j]) ~~^~~~~~~~~~~~