Compilare: user.cpp: In function ‘int main()’: user.cpp:39:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,k,cost=0,a,b; ^ user.cpp:39:22: warning: unused variable ‘a’ [-Wunused-variable] int i,j,k,cost=0,a,b; ^ user.cpp:39:24: warning: unused variable ‘b’ [-Wunused-variable] int i,j,k,cost=0,a,b; ^ user.cpp:37:32: 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:38:34: 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:41:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:43:57: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&(mu[i].x),&(mu[i].y),&(mu[i].c)); ^