Compilare: user.cpp: In function ‘int main()’: user.cpp:49:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<=strlen(nr)-1;i++) ^ user.cpp:45:37: 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:46:39: 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:48:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld\n%s\n%d\n", &a, nr, &c); ^