Compilare: user.cpp: In function ‘void unionn(int, int)’: user.cpp:24:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(a!=b) ^ user.cpp: In function ‘int main()’: user.cpp:34:13: warning: unused variable ‘cod’ [-Wunused-variable] int n,m,cod,x,y,i; ^ user.cpp:34:17: warning: unused variable ‘x’ [-Wunused-variable] int n,m,cod,x,y,i; ^ user.cpp:34:19: warning: unused variable ‘y’ [-Wunused-variable] int n,m,cod,x,y,i; ^ user.cpp:32:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("disjoint.in","r",stdin); ^ user.cpp:33:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("disjoint.out","w",stdout); ^ user.cpp:36:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:39:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&v[i].cod,&v[i].x,&v[i].y); ^