/in/foo.cc: In function 'int main()':
/in/foo.cc:32:24: error: 'a' was not declared in this scope
  while(scanf("%d%d%d",&a,&b,&r)==3 && a!=0) add(a,b,r);
                        ^
/in/foo.cc:32:27: error: 'b' was not declared in this scope
  while(scanf("%d%d%d",&a,&b,&r)==3 && a!=0) add(a,b,r);
                           ^
/in/foo.cc:32:30: error: 'r' was not declared in this scope
  while(scanf("%d%d%d",&a,&b,&r)==3 && a!=0) add(a,b,r);
                              ^