Main.cc: In function 'int main()': Main.cc:8:5: error: 'longlong' was not declared in this scope longlong a,b,c; ^ Main.cc:9:10: error: 'a' was not declared in this scope cin>>a>>b; ^ Main.cc:9:13: error: 'b' was not declared in this scope cin>>a>>b; ^ Main.cc:10:5: error: 'c' was not declared in this scope c=a*10+b; ^