foo.cc: In function 'int main()':
foo.cc:8:14: error: 'a' was not declared in this scope
     float s=(a+b+c)/3.0;
              ^
foo.cc:8:16: error: 'b' was not declared in this scope
     float s=(a+b+c)/3.0;
                ^
foo.cc:8:18: error: 'c' was not declared in this scope
     float s=(a+b+c)/3.0;
                  ^

[Hydro](https://hydro.ac)提供评测服务