Code:I using msvs2010 on vistaOS (so i am told i need to use include<stdafx.h> even though it doesnt appear in my stdlib?) so this is the code teaching me how to use class, in this case Fraction class: #include <stdafx.h> #include <stdlib.h> class Fraction { private: int num, den; public: void set(int n, int d) {num = n; den = d; normalize();} int get_num() {return num;} int get_den() {return den;} private: void normalize(); int gcf(int a, int b); int lcm(int a, int b); }; void Fraction::normalize() { if (den == 0 || num == 0) { num = 0; den = 1; } if (den < 0) { num *= -1; den *= -1; } int n = gcf(num, den); num /= n; den /= n; } int Fraction::gcf(int a, int b) { if (a % b == 0) return abs(b); else return gcf(b, a % b); } int Fraction::lcm(int a, int b) { return (a / gcf(a, b)) * b; } OK, now here the output results: 1>------ Build started: Project: Fract1, Configuration: Debug Win32 ------ 1>Build started 3/10/2011 9:50:21 PM. 1>InitializeBuildStatus: 1> Touching "Debug\Fract1.unsuccessfulbuild". 1>ClCompile: 1> All outputs are up-to-date. 1> All outputs are up-to-date. 1>ManifestResourceCompile: 1> All outputs are up-to-date. 1>MSVCRTD.lib(crtexe.obj) : error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup 1>C:\Users\Jimmy\Documents\Visual Studio 2010\Projects\Fract1\Debug\Fract1.exe : fatal error LNK1120: 1 unresolved externals 1> 1>Build FAILED. 1> 1>Time Elapsed 00:00:00.41 ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== I'm pulling my hair out checking to make sure everything is right and it seems to be, why is it not working? this code is straightoutta the book C++without fear, and the answer code provided with the book. cant wait to hear your answers :)