Compilare: user.cpp: In function ‘int main()’: user.cpp:36:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<b;i++) ^ user.cpp:31:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("calcul.in","r",stdin); ^ user.cpp:32:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("calcul.out","w",stdout); ^ user.cpp:33:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n%x\n%d", &a,&b,&c); ^