Compilare: user.cpp: In function ‘int main()’: user.cpp:33:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1;i<strlen(s)-1;i++) ^ user.cpp:53:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=2;i<=strlen(s)-1;i++) ^ user.cpp:24:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("charlie.in", "r", stdin); ^ user.cpp:25:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("charlie.out", "w", stdout); ^ user.cpp:27:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &p); ^ user.cpp:28:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s\n", s); ^