Compilare: main.cpp: In function 'int main()': main.cpp:60:17: warning: unused variable 'w' [-Wunused-variable] int n,m,i,t,w; ^ main.cpp:58:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("divisorgraph.in","r",stdin); ^ main.cpp:59:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("divisorgraph.out","w",stdout); ^ main.cpp:61:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^ main.cpp:68:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] {scanf("%d%d",&n,&m); ^ main.cpp:74:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^