Compilare: main.cpp: In function 'int main()': main.cpp:20:12: warning: unused variable 'first' [-Wunused-variable] int n,i,k,first=0,last=0,x,a,b,ok; ^~~~~ main.cpp:20:20: warning: unused variable 'last' [-Wunused-variable] int n,i,k,first=0,last=0,x,a,b,ok; ^~~~ main.cpp:20:29: warning: unused variable 'a' [-Wunused-variable] int n,i,k,first=0,last=0,x,a,b,ok; ^ main.cpp:20:31: warning: unused variable 'b' [-Wunused-variable] int n,i,k,first=0,last=0,x,a,b,ok; ^ main.cpp:20:33: warning: unused variable 'ok' [-Wunused-variable] int n,i,k,first=0,last=0,x,a,b,ok; ^~