Compilare: user.cpp: In function ‘void buildF()’: user.cpp:12:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j != -1 && a[j]!=a[f[j-1]]) ^ user.cpp: In function ‘int main()’: user.cpp:22:36: 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:23:38: 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); ^ user.cpp:25:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s%s", a, b); ^