Compilare: user.cpp: In function ‘void modify()’: user.cpp:65:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<=s.size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:102:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.in", "r", stdin); ^ user.cpp:103:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.out", "w", stdout); ^ user.cpp:108:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &n); ^ user.cpp:113:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &c); ^