Compilare: user.cpp: In function ‘int main()’: user.cpp:12:17: warning: suggest parentheses around ‘-’ inside ‘>>’ [-Wparentheses] start=1; s=s-(n*(n+1))>>1; ^ user.cpp:9:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("noname3.in","r",stdin); ^ user.cpp:10:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("noname3.out","w",stdout); ^ user.cpp:11:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld%ld",&n,&s); ^