Compilare: user.cpp: In function ‘int main()’: user.cpp:24:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1 ; i <= n ; ++i) { ^ user.cpp: In function ‘unsigned int solve(unsigned int)’: user.cpp:42:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1 ; i <= n ; ++i) { ^ user.cpp:45:13: warning: unused variable ‘x’ [-Wunused-variable] int x = c.size(); ^ user.cpp: In function ‘int main()’: user.cpp:19:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("secv5.in" , "r" , stdin); ^ user.cpp:20:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("secv5.out" , "w" , stdout); ^ user.cpp:22:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d" , &n , &p , &u);//f >> n >> p >> u; ^ user.cpp:25:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &v[i]);//f >> v[i]; ^