Compilare: user.cpp: In function ‘int main()’: user.cpp:40:19: warning: unused variable ‘nod’ [-Wunused-variable] int i,j,o,k=0,nod,no; ^~~ user.cpp:40:23: warning: unused variable ‘no’ [-Wunused-variable] int i,j,o,k=0,nod,no; ^~ user.cpp:43:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&n,&m); ^ user.cpp:46:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&i,&j); ^