Compilare: user.cpp: In function ‘int main()’: user.cpp:49:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(stiva.size() > vf) { ^ user.cpp: In function ‘int caut_bin(int)’: user.cpp:77:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 1 ; i < v[pos].size() ; i <<= 1); ^ user.cpp:79:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i + p < v[pos].size() && v[pos][p + i] <= vf) { ^ user.cpp: In function ‘int main()’: user.cpp:36:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("undo2.in" , "r" , stdin); ^ user.cpp:37:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("undo2.out" , "w" , stdout); ^