Main.cc: In function ‘int main()’: Main.cc:5:10: error: ‘M’ was not declared in this scope cin>>n>>M>>x>>y; ^ Main.cc:9:3: error: ‘col’ was not declared in this scope col[a]++; ^~~ Main.cc:9:3: note: suggested alternative: ‘atol’ col[a]++; ^~~ atol Main.cc:14:3: error: ‘row’ was not declared in this scope row[a]++; ^~~