Code:h: #include <cstdlib> #include <iostream> class rectangle{ int x,y; rectangle(){ x=0;y=0; } public void v(){ cout<<"dsdsd"<<endl; } }; cpp: #include <cstdlib> #include <iostream> #include "rectangle.h" using namespace std; int main(int argc, char *argv[]) { rectangle r; cout<<r.v()<<endl; system("PAUSE"); return EXIT_SUCCESS; } error: Compiler: Default compiler Building Makefile: "C:\Dev-Cpp\Makefile.win" Executing make... make.exe -f "C:\Dev-Cpp\Makefile.win" all g++.exe -c main.cpp -o main.o -I"C:/Dev-Cpp/lib/gcc/mingw32/3.4.2/include" -I"C:/Dev-Cpp/include/c++/3.4.2/backward" -I"C:/Dev-Cpp/include/c++/3.4.2/mingw32" -I"C:/Dev-Cpp/include/c++/3.4.2" -I"C:/Dev-Cpp/include" In file included from main.cpp:3: rectangle.h:9: error: expected `:' before "void" rectangle.h: In member function `void rectangle::v()': rectangle.h:10: error: `cout' undeclared (first use this function) rectangle.h:10: error: (Each undeclared identifier is reported only once for each function it appears in.) rectangle.h:10: error: `endl' undeclared (first use this function) rectangle.h: In function `int main(int, char**)': rectangle.h:6: error: `rectangle::rectangle()' is private main.cpp:7: error: within this context main.cpp:8: error: `cout' undeclared (first use this function) main.cpp:8: error: `endl' undeclared (first use this function) make.exe: *** [main.o] Error 1 Execution terminated