Compilare: user.cpp: In function ‘int main()’: user.cpp:38:15: warning: unused variable ‘j’ [-Wunused-variable] int n,m,i,j,k=0,x,y; ^ user.cpp:39:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d\n",&n,&m); ^ user.cpp:42:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&x,&y); ^