Compilare: user.cpp: In function ‘int main()’: user.cpp:36:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d " ,&n); ^ user.cpp:38:64: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&son[0][i].first,&son[0][i].second); ^ user.cpp:49:64: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&son[1][i].first,&son[1][i].second); ^ user.cpp:53:9: warning: ‘root1’ may be used uninitialized in this function [-Wmaybe-uninitialized] int root1; ^~~~~ user.cpp:42:9: warning: ‘root0’ may be used uninitialized in this function [-Wmaybe-uninitialized] int root0; ^~~~~