Compilare: user.cpp: In function ‘int main()’: user.cpp:79:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i<strlen(sub_str); i++) ^ user.cpp:88:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i<=strlen(sub_str); i++) pref[i] = 0; ^ user.cpp:65:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("secv10.in","r",stdin); ^ user.cpp:66:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("secv10.out","w",stdout); ^ user.cpp:68:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&T); ^ user.cpp:71:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",str); ^ user.cpp:72:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",sub_str); ^ user.cpp:83:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",sub_str); ^