Compilare: user.cpp: In function ‘int main()’: user.cpp:42:13: warning: unused variable ‘a’ [-Wunused-variable] int n,m,a,b,c,costy=0,nr=0; ^ user.cpp:42:15: warning: unused variable ‘b’ [-Wunused-variable] int n,m,a,b,c,costy=0,nr=0; ^ user.cpp:42:17: warning: unused variable ‘c’ [-Wunused-variable] int n,m,a,b,c,costy=0,nr=0; ^ user.cpp:43:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in","r",stdin); ^ user.cpp:44:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.out","w",stdout); ^ user.cpp:45:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:48:71: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&cost[i].first,&cost[i].second,&cost[i].cost); ^