src.cpp: In function 'int main()':
src.cpp:16:13: error: 'a' was not declared in this scope
fin>>n>>a>>b;
^
src.cpp:16:16: error: 'b' was not declared in this scope
fin>>n>>a>>b;
^
src.cpp:19:14: error: 'x' was not declared in this scope
fin>>x>>y;
^
src.cpp:19:17: error: 'y' was not declared in this scope
fin>>x>>y;
^