Compilare: user.cpp: In function ‘int main()’: user.cpp:84:17: warning: unused variable ‘x’ [-Wunused-variable] int x = 1,y = 1;int len = 0; ^ user.cpp:84:23: warning: unused variable ‘y’ [-Wunused-variable] int x = 1,y = 1;int len = 0; ^ user.cpp:74:9: warning: unused variable ‘n’ [-Wunused-variable] int n,m; ^ user.cpp:74:11: warning: unused variable ‘m’ [-Wunused-variable] int n,m; ^ user.cpp:96:25: warning: ‘a[3]’ may be used uninitialized in this function [-Wmaybe-uninitialized] int a[] = {4*i-3,4*i-2,4*i-1}; ^