Compilare: main.cpp: In function 'int main()': main.cpp:20:10: warning: statement has no effect [-Wunused-value] for(n;n;n--){ ^ main.cpp:16:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("euclid2.in","r",stdin); ^ main.cpp:17:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("euclid2.out","w",stdout); ^ main.cpp:19:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ main.cpp:21:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^