materom.cpp: In function `int main()': materom.cpp:7: `n' undeclared (first use this function) materom.cpp:7: (Each undeclared identifier is reported only once for each function it appears in.) materom.cpp:7: `m' undeclared (first use this function) materom.cpp:8: `i' undeclared (first use this function) materom.cpp:8: `x' undeclared (first use this function) materom.cpp:8: `y' undeclared (first use this function)