Compilare: user.cpp: In function ‘void precomp()’: user.cpp:16:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < pat.length()) { ^ user.cpp: In function ‘int main()’: user.cpp:37:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i <= txt.length()) { ^ user.cpp:38:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j >= pat.length()) { ^