Compilare: user.cpp: In function ‘void KMP(int, int)’: user.cpp:11:61: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (Pi[i] && s[Pi[i]+1] != s[i]) Pi[i] = Pi[Pi[i]]; ^ user.cpp: In function ‘int main()’: user.cpp:24:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("strmatch.in", "r", stdin); ^ user.cpp:25:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("strmatch.out", "w", stdout); ^