Compilare: user.cpp: In function ‘int main()’: user.cpp:89:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (k==s[j].size()-1) { ok=true; break; } ^ user.cpp:111:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (k==s[j].size()-1) k=urm[k]; ^ user.cpp:66:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("adn.in","r",stdin); ^ user.cpp:67:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("adn.out","w",stdout); ^ user.cpp:69:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ",&n); ^ user.cpp:71:17: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(ss); s[i]=ss; s[i].insert(0," "); ^ /tmp/ccBxmFma.o: In function `main': user.cpp:(.text.startup+0x8d): warning: the `gets' function is dangerous and should not be used.