Compilare: user.cpp: In function ‘int main()’: user.cpp:40:13: warning: unused variable ‘j’ [-Wunused-variable] int t,i,j,p,n,m,a,b; ^ user.cpp:38:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("easygraph.in","r",stdin); ^ user.cpp:39:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("easygraph.out","w",stdout); ^ user.cpp:41:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^ user.cpp:44:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:48:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",cost+i); ^ user.cpp:53:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] {scanf("%d%d",&a,&b);add(b,a);} ^