Main.cc: In function ‘int main()’: Main.cc:23:11: error: ‘k2’ was not declared in this scope int k1 = k2 = 1 , k = 0 ^~ Main.cc:23:11: note: suggested alternative: ‘k1’ int k1 = k2 = 1 , k = 0 ^~ k1 Main.cc:24:20: error: ‘i’ was not declared in this scope for ( int i = 1 ; i < n ; i ++ ) ^ Main.cc:45:10: error: ‘ans’ was not declared in this scope cout << ans << endl ; ^~~ Main.cc:45:10: note: suggested alternative: ‘abs’ cout << ans << endl ; ^~~ abs Main.cc:23:6: warning: unused variable ‘k1’ [-Wunused-variable] int k1 = k2 = 1 , k = 0 ^~